JP7689714B2 - Imaging Optical System - Google Patents

Description

The present invention relates to an imaging optical system suitable for photographic lenses used in digital cameras, video cameras, etc.

In recent years, so-called mirrorless cameras have become popular, which do away with the quick-return mirror that is placed between the imaging optical system and the image sensor and directs light to the viewfinder optical system. As the housing of a mirrorless camera has been made more compact by eliminating the mirror, there is a corresponding demand for a more compact imaging optical system. There is also a demand for large-aperture zoom lenses with small maximum apertures across the entire zoom range.

Patent No. 6707987 JP 2019-028258 A

Patent document 1 discloses a bright positive lead type zoom lens with an open F value of about 2.8. However, there is a problem in that the size of the imaging optical system is large. Patent document 2 discloses a positive lead type zoom lens with a compact imaging optical system. However, there is a problem in that the open F value at the telephoto end is about 6.3, which is slow.

The present invention was made in consideration of these circumstances, and aims to provide a compact imaging optical system with a small maximum F-number across the entire zoom range.

In order to achieve the above-mentioned object, an imaging optical system embodying the present invention comprises, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a rear lens group GR having positive refractive power, the rear lens group GR being composed of a plurality of lens groups including a focusing lens group GF that moves when focusing from an object at infinity to an object at a close distance, and satisfies the following conditional expressions:
(1) 1.80<f1/fRW<5.50
(2) 12.0<LTW×FnoT/Ymax<30.0
however,
f1: focal length of the first lens group G1 fRW: focal length of the rear lens group GR when focusing on infinity at the wide-angle end LTW: total optical length of the imaging optical system at the wide-angle end FnoT: maximum F-number of the imaging optical system when focusing on infinity at the telephoto end Ymax: maximum image height of the imaging optical system

In addition, in the imaging optical system embodying the present invention, the lens group located closest to the image surface of the rear lens group GR is preferably fixed with respect to the image surface.

Moreover, the image-forming optical system embodying the present invention preferably satisfies the following conditional expression:
(3) 2.00<f1/fW<6.00
however,
f1: focal length of the first lens group G1 fW: focal length of the imaging optical system at the wide-angle end when focused on infinity

Moreover, the image-forming optical system embodying the present invention preferably satisfies the following conditional expression:
(4) 4.00<f1/|f2|<6.50
however,
f1: focal length of the first lens group G1 f2: focal length of the second lens group G2

In addition, in the imaging optical system embodying the present invention, the first lens group G1 preferably consists of one negative lens and one positive lens.

Moreover, the image-forming optical system embodying the present invention preferably satisfies the following conditional expression:
(5) 1.70<nd1ave
however,
nd1ave: average value of refractive index for d-line of all lenses constituting the first lens group G1

In the image-forming optical system embodying the present invention, the rear lens group GR preferably has a negative lens, the negative lens being located closest to the object side and satisfying the following conditional expression:
(6) vdRn<50
(7) PgFRn+0.0024×νdRn<0.675
however,
νdRn: Abbe number for the d-line of the negative lens located closest to the object among the negative lenses in the rear lens group GR; PgFRn: partial dispersion ratio for the g-line and F-line of the negative lens located closest to the object among the negative lenses in the rear lens group GR;

In addition, in an image-forming optical system embodying the present invention, the rear lens group GR preferably comprises, from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power, the fourth lens group G4 moving along the optical axis when focusing from an object at infinity to an object at a close distance, and satisfying the conditional formula shown below.
(8) 0.40<|f4|/fT<1.50
however,
f4: focal length of the fourth lens group G4 fT: focal length of the imaging optical system at the telephoto end when focused on infinity

In addition, in an imaging optical system embodying the present invention, the third lens group G3 and the fifth lens group G5 preferably move along the same trajectory during magnification change.

Moreover, the image-forming optical system embodying the present invention preferably satisfies the following conditional expression:
(9) BFT/Ymax<2.00
however,
BFT: Back focus of the imaging optical system at the telephoto end Ymax: Maximum image height of the imaging optical system

Moreover, the image-forming optical system embodying the present invention preferably satisfies the following conditional expression:
(10) 0.80<M1/fW<2.00
however,
M1: Amount of movement of the first lens group G1 during magnification change from the wide-angle end to the telephoto end fW: Focal length of the imaging optical system at the wide-angle end when focusing on infinity

In the image-forming optical system embodying the present invention, the rear lens group GR has a vibration-proof lens group GS which moves including a component in a direction perpendicular to the optical axis, and satisfies the following conditional expression.
(11) 0.50<|fS|/fW<4.0
however,
fS: focal length of the vibration-proof lens group GS, fW: focal length of the imaging optical system at the wide-angle end when focused on infinity

By implementing the imaging optical system of the present invention, it is possible to provide a compact imaging optical system with a small maximum F-number across the entire zoom range.

1 is a lens configuration diagram according to a first embodiment of an imaging optical system of the present invention. 4A to 4C are longitudinal aberration diagrams of the imaging optical system of Example 1 at the wide-angle end and the shooting distance at infinity. 4A to 4C are diagrams illustrating lateral aberration at the wide-angle end of the imaging optical system of Example 1 at an infinite shooting distance. 4A to 4C are lateral aberration diagrams of the imaging optical system of Example 1 at the wide-angle end and at a shooting distance of infinity with 0.3° image stabilization. 4A to 4C are longitudinal aberration diagrams of the imaging optical system of Example 1 at a shooting distance of 814 mm at the wide-angle end. 4A to 4C are lateral aberration diagrams of the imaging optical system of Example 1 at a shooting distance of 814 mm at the wide-angle end. 4A to 4C are longitudinal aberration diagrams of the imaging optical system of Example 1 at an object distance of infinity at an intermediate zoom position. 4A to 4C are diagrams illustrating lateral aberration of the imaging optical system of Example 1 at an object distance of infinity at an intermediate zoom position. 4A to 4C are lateral aberration diagrams of the imaging optical system of Example 1 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. 11A and 11B are longitudinal aberration diagrams of the imaging optical system of Example 1 at an object distance of 1,262 mm at an intermediate zoom position. 4A to 4C are diagrams illustrating lateral aberration of the imaging optical system of Example 1 at an object distance of 1,262 mm at an intermediate zoom position. 4A to 4C are longitudinal aberration diagrams of the imaging optical system of Example 1 at the telephoto end with a shooting distance of infinity. 4A to 4C are diagrams illustrating lateral aberration at the telephoto end of the imaging optical system of Example 1 when the shooting distance is infinite. 4A to 4C are lateral aberration diagrams of the imaging optical system of Example 1 at the telephoto end with a shooting distance of infinity and with 0.3° image stabilization. 4A to 4C are longitudinal aberration diagrams of the imaging optical system of Example 1 at a telephoto end and a shooting distance of 1997 mm. 4A to 4C are lateral aberration diagrams of the imaging optical system of Example 1 at a telephoto end and a shooting distance of 1997 mm. FIG. 11 is a lens configuration diagram according to Example 2 of the imaging optical system of the present invention. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 2 at the wide-angle end and the shooting distance at infinity. 11A to 11C are diagrams illustrating lateral aberration of the imaging optical system of Example 2 at the wide-angle end and at a shooting distance of infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 2 at the wide-angle end and at a shooting distance of infinity with 0.3° image stabilization. 11A to 11C are longitudinal aberration diagrams of the imaging optical system of Example 2 at a shooting distance of 811 mm at the wide-angle end. 11A to 11C are lateral aberration diagrams of the imaging optical system of Example 2 at a shooting distance of 811 mm at the wide-angle end. 13A and 13B are longitudinal aberration diagrams of the imaging optical system of Example 2 at an object distance of infinity in an intermediate zoom range. 13A and 13B are diagrams illustrating lateral aberration of the imaging optical system of Example 2 at an object distance of infinity at an intermediate zoom position. 13A and 13B are lateral aberration diagrams of the imaging optical system of Example 2 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. 11A and 11B are longitudinal aberration diagrams of the imaging optical system of Example 2 at an object distance of 1,259 mm in the intermediate zoom range. 11A and 11B are diagrams illustrating lateral aberration of the imaging optical system of Example 2 at an object distance of 1,259 mm at an intermediate zoom position. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 2 at the telephoto end with a shooting distance of infinity. 11A to 11C are diagrams illustrating lateral aberration at the telephoto end of the imaging optical system of Example 2 when the shooting distance is infinite. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 2 at the telephoto end and at a shooting distance of infinity with 0.3° image stabilization. 11A to 11C are longitudinal aberration diagrams of the imaging optical system of Example 2 at a telephoto end and an object distance of 1997 mm. 11A to 11C are lateral aberration diagrams of the imaging optical system of Example 2 at a telephoto end and a shooting distance of 1997 mm. FIG. 11 is a lens configuration diagram according to Example 3 of the imaging optical system of the present invention. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 3 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 3 at the wide-angle end and at a shooting distance of infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 3 at the wide-angle end and at a shooting distance of infinity with 0.3° vibration reduction. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 3 at a shooting distance of 808 mm at the wide-angle end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 3 at a shooting distance of 808 mm at the wide-angle end. 13A and 13B are longitudinal aberration diagrams of the imaging optical system of Example 3 at an object distance of infinity in an intermediate zoom range. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 3 at an object distance of infinity at an intermediate zoom position. 13A and 13B are lateral aberration diagrams of the imaging optical system of Example 3 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 3 at an object distance of 1,263 mm in the middle zoom range. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 3 at an object distance of 1,263 mm at an intermediate zoom position. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 3 at the telephoto end with a shooting distance of infinity. 13A to 13C are diagrams illustrating lateral aberration at the telephoto end of the imaging optical system of Example 3 when the shooting distance is infinite. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 3 at the telephoto end with a shooting distance of infinity and with 0.3° image stabilization. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 3 at a telephoto end and an object distance of 2000 mm. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 3 at a telephoto end and an object distance of 2000 mm. FIG. 11 is a lens configuration diagram according to Example 4 of the imaging optical system of the present invention. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 4 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 4 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 4 at the wide-angle end and at a shooting distance of infinity with 0.3° vibration reduction. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 4 at a shooting distance of 808 mm at the wide-angle end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 4 at a shooting distance of 808 mm at the wide-angle end. 13A and 13B are longitudinal aberration diagrams of the imaging optical system of Example 4 at an object distance of infinity in an intermediate zoom range. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 4 at an object distance of infinity at an intermediate zoom position. 13A and 13B are lateral aberration diagrams of the imaging optical system of Example 4 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 4 at an object distance of 1,267 mm in the intermediate zoom range. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 4 at an object distance of 1,267 mm at an intermediate zoom position. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 4 at the telephoto end with a shooting distance of infinity. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 4 at the telephoto end and at a shooting distance of infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 4 at the telephoto end with a shooting distance of infinity and with 0.3° image stabilization. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 4 at a shooting distance of 1997 mm at the telephoto end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 4 at a telephoto end and a shooting distance of 1997 mm. FIG. 11 is a lens configuration diagram according to Example 5 of the imaging optical system of the present invention. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 5 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 5 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 5 at the wide-angle end and at a shooting distance of infinity with 0.3° vibration reduction. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 5 at a shooting distance of 808 mm at the wide-angle end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 5 at a shooting distance of 808 mm at the wide-angle end. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 5 at an object distance of infinity at an intermediate zoom position. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 5 at an object distance of infinity at an intermediate zoom position. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 5 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 5 at an object distance of 1,257 mm at an intermediate zoom position. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 5 at an object distance of 1,257 mm at an intermediate zoom position. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 5 at the telephoto end with a shooting distance of infinity. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 5 at the telephoto end when the shooting distance is infinite. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 5 at the telephoto end and at a shooting distance of infinity with 0.3° image stabilization. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 5 at a telephoto end and a shooting distance of 1993 mm. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 5 at a telephoto end and a shooting distance of 1993 mm. FIG. 13 is a lens configuration diagram according to Example 6 of the imaging optical system of the present invention. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 6 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 6 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 6 at the wide-angle end and at a shooting distance of infinity with 0.3° vibration reduction. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 6 at a shooting distance of 802 mm at the wide-angle end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 6 at a shooting distance of 802 mm at the wide-angle end. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 6 at an object distance of infinity in an intermediate zoom range. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 6 at an object distance of infinity at an intermediate zoom position. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 6 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. 13 is a longitudinal aberration diagram of the imaging optical system of Example 6 at a shooting distance of 1254 mm in the middle zoom position. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 6 at an object distance of 1,254 mm at an intermediate zoom position. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 6 at the telephoto end with a shooting distance of infinity. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 6 at the telephoto end when the shooting distance is infinite. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 6 at the telephoto end with a shooting distance of infinity and with 0.3° image stabilization. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 6 at a telephoto end and an object distance of 2184 mm. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 6 at a telephoto end and an object distance of 2184 mm. FIG. 13 is a lens configuration diagram according to Example 7 of the imaging optical system of the present invention. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 7 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 7 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 7 at the wide-angle end and at a shooting distance of infinity with 0.3° vibration reduction. 13 is a longitudinal aberration diagram of the imaging optical system of Example 7 at a shooting distance of 717 mm at the wide-angle end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 7 at a shooting distance of 717 mm at the wide-angle end. 13 is a longitudinal aberration diagram of the imaging optical system of Example 7 at an object distance of infinity in an intermediate zoom range. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 7 at an object distance of infinity at an intermediate zoom position. 13 is a lateral aberration diagram of the imaging optical system of Example 7 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. FIG. FIG. 13 is a longitudinal aberration diagram of the imaging optical system of Example 7 at a shooting distance of 1,125 mm at an intermediate zoom position. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 7 at an object distance of 1,125 mm at an intermediate zoom position. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 7 at the telephoto end with a shooting distance of infinity. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 7 at the telephoto end and at a shooting distance of infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 7 at the telephoto end and an object distance of infinity with 0.3° image stabilization. 13 is a longitudinal aberration diagram of the imaging optical system of Example 7 at a telephoto end and a shooting distance of 1615 mm. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 7 at a shooting distance of 1615 mm at the telephoto end. FIG. 13 is a lens configuration diagram according to Example 8 of the imaging optical system of the present invention. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 8 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 8 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 8 at the wide-angle end and the shooting distance at infinity, with 0.3° vibration reduction. 13 is a longitudinal aberration diagram of the imaging optical system of Example 8 at a shooting distance of 758 mm at the wide-angle end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 8 at a shooting distance of 758 mm at the wide-angle end. 13 is a longitudinal aberration diagram of the imaging optical system of Example 8 at an object distance of infinity in an intermediate zoom range. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 8 at an object distance of infinity at an intermediate zoom position. FIG. 23 is a lateral aberration diagram of the imaging optical system of Example 8 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. FIG. 13 is a longitudinal aberration diagram of the imaging optical system of Example 8 at a shooting distance of 1257 mm in the middle zoom position. 13 is a lateral aberration diagram of the imaging optical system of Example 8 at a shooting distance of 1257 mm at an intermediate zoom position. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 8 at the telephoto end with a shooting distance of infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 8 at the telephoto end and at a shooting distance of infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 8 at the telephoto end and an object distance of infinity with 0.3° image stabilization. 13 is a longitudinal aberration diagram of the imaging optical system of Example 8 at a shooting distance of 1992 mm at the telephoto end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 8 at a shooting distance of 1992 mm at the telephoto end. FIG. 13 is a lens configuration diagram of an imaging optical system according to a ninth embodiment of the present invention. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 9 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 9 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 9 at the wide-angle end and the shooting distance at infinity, with 0.3° image stabilization. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 9 at a shooting distance of 1,024 mm at the wide-angle end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 9 at the wide-angle end and the shooting distance of 1024 mm. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 9 at an object distance of infinity at an intermediate zoom position. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 9 at an object distance of infinity at an intermediate zoom position. FIG. 13 is a lateral aberration diagram of the imaging optical system of Example 9 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. FIG. 13 is a longitudinal aberration diagram of the imaging optical system of Example 9 at a shooting distance of 1664 mm at an intermediate zoom position. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 9 at an object distance of 1664 mm at an intermediate zoom position. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 9 at the telephoto end with a shooting distance of infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 9 at the telephoto end and at a shooting distance of infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 9 at the telephoto end with a shooting distance of infinity and with 0.3° image stabilization. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 9 at a shooting distance of 2777 mm at the telephoto end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 9 at a shooting distance of 2777 mm at the telephoto end. FIG. 13 is a lens configuration diagram according to Example 10 of the imaging optical system of the present invention. 23A to 23C are longitudinal aberration diagrams of the imaging optical system of Example 10 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 10 at the wide-angle end and the shooting distance at infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 10 at the wide-angle end and an object distance of infinity with 0.3° vibration reduction. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 10 at a shooting distance of 1,241 mm at the wide-angle end. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 10 at the wide-angle end and a shooting distance of 1241 mm. FIG. 23 is a longitudinal aberration diagram of the imaging optical system of Example 10 at an object distance of infinity at an intermediate zoom position. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 10 at an object distance of infinity at an intermediate zoom position. FIG. 23 is a lateral aberration diagram of the imaging optical system of Example 10 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. FIG. 23 is a longitudinal aberration diagram of the imaging optical system of Example 10 at an object distance of 1892 mm at an intermediate zoom position. FIG. 23 is a lateral aberration diagram of the imaging optical system of Example 10 at a shooting distance of 1892 mm at an intermediate zoom position. 13A to 13C are longitudinal aberration diagrams of the imaging optical system of Example 10 at the telephoto end with a shooting distance of infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 10 at the telephoto end with a shooting distance of infinity. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 10 at the telephoto end with a shooting distance of infinity and with 0.3° image stabilization. FIG. 23 is a longitudinal aberration diagram of the imaging optical system of Example 10 at a telephoto end and a shooting distance of 2986 mm. 13A to 13C are lateral aberration diagrams of the imaging optical system of Example 10 at a telephoto end and a shooting distance of 2986 mm. FIG. 13 is a lens configuration diagram according to an eleventh embodiment of the imaging optical system of the present invention. 16A to 16C are longitudinal aberration diagrams of the imaging optical system of Example 11 at the wide-angle end and the shooting distance at infinity. 16A to 16C are lateral aberration diagrams of the imaging optical system of Example 11 at the wide-angle end and the shooting distance at infinity. FIG. 23 is a lateral aberration diagram of the imaging optical system of Example 11 at the wide-angle end and at a shooting distance of infinity with 0.3° vibration reduction. 16 is a longitudinal aberration diagram of the imaging optical system of Example 11 at the wide-angle end and a shooting distance of 811 mm. 16A to 16C are lateral aberration diagrams of the imaging optical system of Example 11 at the wide-angle end and a shooting distance of 811 mm. FIG. 23 is a longitudinal aberration diagram of the image forming optical system of Example 11 at an object distance of infinity at an intermediate zoom position. 13A to 13C are diagrams illustrating lateral aberration of the imaging optical system of Example 11 at an object distance of infinity at an intermediate zoom position. FIG. 23 is a lateral aberration diagram of the imaging optical system of Example 11 at an object distance of infinity at an intermediate zoom position and with 0.3° image stabilization. FIG. 23 is a longitudinal aberration diagram of the imaging optical system of Example 11 at a shooting distance of 1,266 mm at an intermediate zoom position. FIG. 23 is a lateral aberration diagram of the imaging optical system of Example 11 at a shooting distance of 1,266 mm at an intermediate zoom position. 16A to 16C are longitudinal aberration diagrams of the imaging optical system of Example 11 at the telephoto end with a shooting distance of infinity. 16A to 16C are lateral aberration diagrams of the imaging optical system of Example 11 at the telephoto end with a shooting distance of infinity. FIG. 23 is a lateral aberration diagram of the imaging optical system of Example 11 at the telephoto end with a shooting distance of infinity and with 0.3° image stabilization. FIG. 23 is a longitudinal aberration diagram of the imaging optical system of Example 11 at a telephoto end and a shooting distance of 2005 mm. 16A to 16C are lateral aberration diagrams of the imaging optical system of Example 11 at a telephoto end and a shooting distance of 2005 mm.

Hereinafter, an embodiment of the present invention will be described. When the refractive indices for the g-line (wavelength 435.8 nm), F-line (wavelength 486.1 nm), d-line (wavelength 587.6 nm), and C-line (wavelength 656.3 nm) are ng, nF, nd, and nC, respectively, the Abbe number vd and the partial dispersion ratio θgF are expressed by the following formulas.
νd=(nd-1)/(nF-nC)
θgF=(ng-nF)/(nF-nC)

As can be seen from Figures 1, 17, 33, 49, 65, 81, 97, 113, 129, 145, and 161, the imaging optical system of the present invention comprises, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a rear lens group GR having positive refractive power, the rear lens group GR being composed of a plurality of lens groups including a focusing lens group GF that moves when focusing from an object at infinity to an object at a close distance, and is characterized in that it satisfies the following conditional formula:
(1) 1.80<f1/fRW<5.50
(2) 12.0<LTW×FnoT/Ymax<30.0
where f1: focal length of the first lens group G1, fRW: focal length of the rear lens group GR when focusing on infinity at the wide-angle end, LTW: total optical length of the imaging optical system at the wide-angle end, FnoT: maximum F-number of the imaging optical system at the telephoto end when focusing on infinity, Ymax: maximum image height of the imaging optical system

Conditional formula (1) defines the ratio of the focal lengths of the first lens group G1 and the rear lens group GR at the wide-angle end, allowing for both compactness and correction of various aberrations.

When the refractive power of the first lens group G1 weakens beyond the upper limit of conditional formula (1), the amount of movement of the first lens group G1 during zooming increases, which in turn increases the mechanisms required for movement and results in an increase in the size of the lens barrel. In addition, the overall optical length at the telephoto end increases, making it difficult to ensure the peripheral illumination ratio at the telephoto end, and in order to ensure the peripheral illumination ratio, the diameter of the first lens group G1 must be increased, resulting in an increase in the size of the imaging optical system. In addition, when the refractive power of the rear lens group GR becomes strong, it becomes difficult to suppress the spherical aberration and coma aberration that occur in the rear lens group GR.

When the refractive power of the first lens group G1 becomes strong beyond the lower limit of conditional formula (1), it becomes difficult to suppress the astigmatism that occurs in the first lens group G1. In addition, when the refractive power of the rear lens group GR becomes weak, the effect of converging the light beam diffused by the second lens group G2 becomes weak, so the total length of the rear lens group GR becomes long and the diameter becomes large, leading to an increase in the size of the imaging optical system.

Regarding conditional expression (1), it is preferable to set the lower limit to 2.20 and the upper limit to 4.50 to ensure the above-mentioned effect.

Conditional formula (2) specifies the ratio between the total optical length at the wide-angle end of the imaging optical system, the maximum aperture F-number at the telephoto end, and the maximum image height, thereby ensuring the brightness of the imaging optical system, making it compact, and correcting various aberrations.

In general, the smaller the F-number of an optical system, the higher the axial rays passing through it. Also, the higher the maximum image height, the higher the off-axial rays passing through the group closest to the object side or closest to the image plane side. This corresponds to the FnoT/Ymax component in conditional formula (2) becoming smaller. In order to correct the various aberrations in such a situation, it is effective to increase the overall length of the optical system and make the incident rays on each surface within the optical system gentler, but to achieve this while also being compact, it is necessary to set the overall length appropriately according to the F-number at the telephoto end and the maximum image height.

If the upper limit of conditional expression (2) is exceeded and the total optical length at the wide-angle end becomes large relative to the ratio of the F-number at the telephoto end to the maximum image height, it becomes easier to suppress the various aberrations that occur throughout the entire system, but the total length of the optical system becomes long. Or, the F-number at the telephoto end becomes large, making it difficult to achieve a bright optical system.

When the lower limit of conditional formula (2) is exceeded and the total optical length at the wide-angle end becomes small relative to the ratio of the F-number at the telephoto end to the maximum image height, the total length is kept short, but the refraction of light rays within the optical system becomes stronger, increasing the aberrations that occur in each group, making it difficult to satisfactorily correct fluctuations such as astigmatism, spherical aberration, and coma aberration that occur mainly when changing magnification.

Regarding conditional expression (2), it is preferable to limit the lower limit to 15.0 and the upper limit to 26.0, thereby ensuring the above-mentioned effect. Furthermore, in order to achieve an optical system with a smaller F-number at the telephoto end and a shorter overall length, the upper limit should be limited to 21.0, which will enable an optical system with a smaller F-number at the telephoto end and a shorter overall length to be achieved.

Furthermore, in the imaging optical system of the present invention, it is desirable that the lens group located closest to the image surface is fixed with respect to the image surface. By fixing the lens group located closest to the image surface when changing magnification, the mechanism required for changing magnification can be simplified and the lens barrel can be made more compact.

Furthermore, in the image-forming optical system of the present invention, it is desirable to satisfy the following conditional expression:
(3) 2.00<f1/fW<6.00
however,
f1: focal length of the first lens group G1 fW: focal length of the imaging optical system at the wide-angle end when focused on infinity

Condition (3) defines the ratio of the focal length of the first lens group G1 to that of the imaging optical system at the wide-angle end, allowing for both compactness and correction of various aberrations.

When the refractive power of the first lens group G1 weakens beyond the upper limit of conditional expression (3), the amount of movement of the first lens group G1 during magnification change increases, which requires more mechanisms for movement and results in a larger lens barrel. In addition, the overall optical length at the telephoto end increases, making it difficult to ensure the peripheral illumination ratio at the telephoto end. In order to ensure the peripheral illumination ratio, the diameter of the first lens group G1 must be increased, resulting in a larger imaging optical system.

When the refractive power of the first lens group G1 becomes too strong beyond the lower limit of conditional expression (3), it becomes difficult to suppress the spherical aberration and astigmatism that occur in the first lens group G1.

Regarding conditional expression (3), it is preferable to limit the lower limit to 2.50 and the upper limit to 5.00 in order to ensure the above-mentioned effect.

Furthermore, in the image-forming optical system of the present invention, it is desirable to satisfy the following conditional expression:
(4) 4.00<f1/|f2|<6.50
however,
f1: focal length of the first lens group G1 f2: focal length of the second lens group G2

Conditional formula (4) defines the ratio of the focal lengths of the first lens group G1 and the second lens group G2, allowing for both compactness and correction of various aberrations.

When the refractive power of the first lens group G1 weakens beyond the upper limit of conditional expression (4), the amount of movement of the first lens group G1 during zooming increases, which increases the mechanisms required for movement and leads to a larger lens barrel. In addition, the overall optical length at the telephoto end increases, making it difficult to ensure the peripheral illumination ratio at the telephoto end, and in order to ensure the peripheral illumination ratio, the diameter of the first lens group G1 needs to be increased, leading to a larger imaging optical system. In addition, when the refractive power of the second lens group G2 becomes strong, it becomes difficult to suppress the coma aberration at the telephoto end and the astigmatism at the wide-angle end that occur in the second lens group G2.

When the refractive power of the first lens group G1 becomes too strong beyond the lower limit of conditional expression (4), it becomes difficult to suppress the astigmatism that occurs in the first lens group G1. Also, when the refractive power of the second lens group G2 becomes too weak, the amount of movement of the second lens group G2 during zooming increases, and the mechanisms required for movement increase, leading to an increase in the size of the lens barrel.

Regarding conditional expression (4), it is preferable to limit the lower limit to 4.30 and the upper limit to 5.70 in order to ensure the above-mentioned effect.

Furthermore, in the imaging optical system of the present invention, it is desirable that the first lens group G1 consists of one negative lens and one positive lens. By configuring the first lens group G1 with two lenses, the overall length of the first lens group G1 can be kept short, and the structure for holding the lenses can be simplified, making it possible to miniaturize the imaging optical system. In addition, by combining a negative lens and a positive lens, chromatic aberration occurring in the first lens group G1 can be suppressed.

Furthermore, in the image-forming optical system of the present invention, it is desirable to satisfy the following conditional expression:
(5) 1.70<nd1ave
however,
nd1ave: average value of refractive index for d-line of all lenses constituting the first lens group G1

Conditional formula (5) defines the average value of the refractive index of all the lenses that make up the first lens group G1.

If the refractive index of the lenses constituting the first lens group G1 becomes small beyond the lower limit of conditional expression (5), the radius of curvature of the lens surface becomes small, making it difficult to correct coma aberration.

It is preferable to set the lower limit of conditional expression (5) to 1.76 to ensure the above-mentioned effect.

Furthermore, in the image-forming optical system of the present invention, it is desirable that the rear lens group GR has a negative lens, and that the negative lens positioned closest to the object side among them satisfies the condition shown below.
(6) vdRn<50
(7) PgFRn+0.0024×νdRn<0.675
however,
νdRn: Abbe number for the d-line of the negative lens located closest to the object among the negative lenses in the rear lens group GR; PgFRn: partial dispersion ratio for the g-line and F-line of the negative lens located closest to the object among the negative lenses in the rear lens group GR;

Conditional expressions (6) and (7) stipulate the optical characteristics that are preferable for effectively correcting chromatic aberration for the material of the negative lens located closest to the object among the negative lenses in the rear lens group GR. By using a high-dispersion optical material with negative anomalous partial dispersion as the material of the negative lens located closest to the object among the negative lenses in the rear lens group GR, fluctuations in chromatic aberration, including secondary spectrum, during zooming are suppressed.

When the upper limit of conditional expression (6) is exceeded and the Abbe number of the negative lens in the rear lens group GR that is located closest to the object becomes small, the achromatic effect of the rear lens group GR becomes small, making it difficult to suppress chromatic aberration.

It is preferable to set the upper limit of conditional expression (6) to 41.0 to ensure the above-mentioned effect.

When the upper limit of conditional expression (7) is exceeded and the anomalous partial dispersion of the negative lens in the rear lens group GR that is located closest to the object becomes small, the achromatic effect, including the secondary spectrum, in the rear lens group GR becomes small, making it difficult to suppress chromatic aberration.

It is preferable to set the upper limit of conditional expression (7) to 0.672 in order to ensure the above-mentioned effect.

Furthermore, in the imaging optical system of the present invention, the rear lens group GR consists of, from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power, and it is desirable that the fourth lens group G4 moves along the optical axis when focusing from an object at infinity to an object at a close distance, and that it satisfies the conditional formula shown below.
(8) 0.40<|f4|/fT<1.50
however,
f4: focal length of the fourth lens group G4 fT: focal length of the imaging optical system at the telephoto end when focused on infinity

Conditional expression (8) defines the ratio between the focal length of the fourth lens group G4, which moves during focusing, and the focal length of the imaging optical system at the telephoto end, thereby achieving both compactness and correction of various aberrations.

When the refractive power of the fourth lens group G4 becomes weaker beyond the upper limit of conditional expression (8), the movement distance of the fourth lens group G4 during focusing becomes large, making it difficult to shorten the overall length of the optical system.

If the refractive power of the fourth lens group G4 becomes too strong beyond the lower limit of conditional expression (8), it becomes difficult to suppress the astigmatism generated in the fourth lens group G4, and the aberration fluctuation during focusing becomes large. In addition, the amount of aberration fluctuation when the fourth lens group G4 becomes decentered also becomes large, which is undesirable.

Regarding conditional expression (8), it is preferable to limit the lower limit to 0.45 and the upper limit to 1.20 in order to ensure the above-mentioned effect.

Furthermore, in the imaging optical system of the present invention, it is desirable that the third lens group G3 and the fifth lens group G5 move on the same trajectory when changing magnification. This allows the mechanisms required for moving the third lens group G3 and the fifth lens group G5 when changing magnification to be the same, simplifying the structure and enabling the lens barrel to be made more compact.

Furthermore, in the image-forming optical system of the present invention, it is desirable to satisfy the following conditional expression:
(9) BFT/Ymax<2.00
however,
BFT: Back focus of the imaging optical system at the telephoto end Ymax: Maximum image height of the imaging optical system

Conditional formula (9) specifies the ratio of the back focus to the maximum image height in the imaging optical system, making it possible to reduce the size of the system. Here, the back focus is the air-equivalent length on the optical axis from the surface of the rear lens group GR closest to the image plane to the image plane.

If the back focus becomes large beyond the upper limit of condition (9), the overall length becomes long, which is undesirable.

It is preferable to set the upper limit of conditional expression (9) to 1.65 to ensure the above-mentioned effect.

Furthermore, in the image-forming optical system of the present invention, it is desirable to satisfy the following conditional expression:
(10) 0.80<M1/fW<2.00
however,
M1: Amount of movement of the first lens group G1 during magnification change from the wide-angle end to the telephoto end fW: Focal length of the imaging optical system at the wide-angle end when focusing on infinity

Condition (10) allows for compactness by defining the amount of movement of the first lens group G1 from the wide-angle end to the telephoto end and the total optical length of the imaging optical system at the wide-angle end.

If the amount of movement of the first lens group G1 from the wide-angle end to the telephoto end becomes large beyond the upper limit of conditional expression (10), the number of mechanisms required for movement increases, leading to an increase in the size of the lens barrel. In addition, the overall optical length at the telephoto end becomes long, making it difficult to ensure the peripheral illumination ratio at the telephoto end, and in order to ensure the peripheral illumination ratio, it is necessary to increase the diameter of the first lens group G1, which leads to an increase in the size of the imaging optical system, which is not desirable.

When the lower limit of conditional expression (10) is exceeded and the amount of movement of the first lens group G1 from the wide-angle end to the telephoto end becomes small, it becomes necessary to increase the refractive power of the first lens group G1, making it difficult to suppress the spherical aberration and astigmatism that occur in the first lens group G1.

Regarding conditional expression (10), it is preferable to limit the lower limit to 0.95 and the upper limit to 1.70 in order to ensure the above-mentioned effect.

Furthermore, in the image-forming optical system of the present invention, it is desirable that the rear lens group GR has a vibration-proof lens group GS which moves including a component in a direction perpendicular to the optical axis, and that the following conditional expression is satisfied:
(11) 0.50<|fS|/fW<4.0
however,
fS: focal length of the vibration-proof lens group GS, fW: focal length of the imaging optical system at the wide-angle end when focused on infinity

Condition (11) defines the ratio of the focal lengths of the image stabilization lens group GS and the imaging optical system at the wide-angle end when focused at infinity, making it possible to achieve both a high image stabilization effect and good imaging performance.

When the refractive power of the vibration-reduction lens group GS becomes small beyond the upper limit of conditional expression (11), the amount of movement during vibration reduction increases, resulting in a decrease in vibration reduction responsiveness and an increase in the size of the lens barrel.

When the refractive power of the image stabilization lens group GS becomes large beyond the lower limit of conditional expression (11), the aberration fluctuation during image stabilization becomes large.

Regarding conditional expression (11), it is preferable to limit the lower limit to 0.80 and the upper limit to 2.20 to ensure the above-mentioned effect.

Next, we will explain the lens configuration of an embodiment of the imaging optical system of the present invention. In the following explanation, the lens configuration will be described in order from the object side to the image surface side.

Figure 1 is a lens configuration diagram of an imaging optical system according to a first embodiment of the present invention.

The imaging optical system of Example 1 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. When changing magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image surface. The fourth lens group G4 is a focusing lens group GF, and moves along the optical axis toward the image surface when focusing from an object at infinity to an object at a close distance. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a cemented lens of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and an aspheric R1 surface, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image surface side. The third lens group G3 is composed of a biconvex lens L7 with both R1 and R2 surfaces aspheric, a cemented lens of a biconcave lens L8 and a convex meniscus lens L9 with a convex surface facing the object side, and a biconvex lens L10 with both R1 and R2 surfaces aspheric. The biconvex lens L10 is an anti-vibration lens group GS, and moves with a component perpendicular to the optical axis during anti-vibration. The fourth lens group G4 is composed of a concave meniscus lens L11 with a convex surface facing the object side. The fifth lens group G5 consists of a biconcave lens L12. The sixth lens group G6 consists of a biconvex lens L13.

Figure 17 is a lens configuration diagram of the imaging optical system according to the second embodiment of the present invention.

The imaging optical system of Example 2 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. When changing magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image surface. The fourth lens group G4 is a focusing lens group GF, and moves along the optical axis toward the image surface when focusing from an object at infinity to an object at a close distance. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a cemented lens of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and an aspheric R1 surface, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image surface side. The third lens group G3 is composed of a biconvex lens L7 with both R1 and R2 surfaces aspheric, a cemented lens of a concave meniscus lens L8 with a convex surface facing the object side and a convex meniscus lens L9 with a convex surface facing the object side, and a biconvex lens L10 with both R1 and R2 surfaces aspheric. The biconvex lens L10 is an anti-vibration lens group GS, and moves with a component perpendicular to the optical axis during anti-vibration. The fourth lens group G4 is composed of a concave meniscus lens L11 with a convex surface facing the object side. The fifth lens group G5 consists of a biconcave lens L12. The sixth lens group G6 consists of a biconvex lens L13.

Figure 33 is a lens configuration diagram of the imaging optical system according to the third embodiment of the present invention.

The imaging optical system of Example 3 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. When changing magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image surface. The fourth lens group G4 is a focusing lens group GF, and moves along the optical axis toward the image surface when focusing from an object at infinity to an object at a close distance. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a cemented lens of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and an aspheric R1 surface, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image surface side. The third lens group G3 is composed of a biconvex lens L7 with both R1 and R2 surfaces aspheric, a cemented lens of a biconcave lens L8 and a convex meniscus lens L9 with a convex surface facing the object side, and a biconvex lens L10 with both R1 and R2 surfaces aspheric. The biconvex lens L10 is an anti-vibration lens group GS, and moves with a component perpendicular to the optical axis during anti-vibration. The fourth lens group G4 is composed of a concave meniscus lens L11 with a convex surface facing the object side. The fifth lens group G5 consists of a biconcave lens L12. The sixth lens group G6 consists of a biconvex lens L13.

Figure 49 is a lens configuration diagram of the imaging optical system according to the fourth embodiment of the present invention.

The imaging optical system of Example 4 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. When changing magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image plane. The fourth lens group G4 is a focusing lens group GF, and moves along the optical axis toward the image surface when focusing from an object at infinity to an object at a close distance. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and an aspheric R1 surface, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image surface side. The third lens group G3 is composed of a convex meniscus lens L7 with a convex surface facing the object side and both R1 and R2 surfaces being aspheric, a cemented lens of a concave meniscus lens L8 with a convex surface facing the object side and a biconvex lens L9, and a biconvex lens L10 with both R1 and R2 surfaces being aspheric. The biconvex lens L10 is an anti-vibration lens group GS, and moves with a component perpendicular to the optical axis during anti-vibration. The fourth lens group G4 is composed of a concave meniscus lens L11 with a convex surface facing the object side. The fifth lens group G5 consists of a concave meniscus lens L12 with a convex surface facing the image side. The sixth lens group G6 consists of a convex meniscus lens L13 with a convex surface facing the image side.

Figure 65 is a lens configuration diagram of the imaging optical system according to the fifth embodiment of the present invention.

The imaging optical system of Example 5 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. When changing the magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image surface. The fourth lens group G4 is a focusing lens group GF, and moves along the optical axis toward the image surface when focusing from an object at infinity to an object at a close distance. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a cemented lens of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and an aspheric R1 surface, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image surface side. The third lens group G3 is composed of a biconvex lens L7 with both R1 and R2 surfaces aspheric, a cemented lens of a biconcave lens L8 and a convex meniscus lens L9 with a convex surface facing the object side, a concave meniscus lens L10 with a convex surface facing the image surface side, a convex meniscus lens L11 with a convex surface facing the image surface side, and a biconvex lens L12 with both R1 and R2 surfaces aspheric. The biconvex lens L12 is an anti-vibration lens group GS, and moves with a component perpendicular to the optical axis during anti-vibration. The fourth lens group G4 consists of a concave meniscus lens L13 with a convex surface facing the object side. The fifth lens group G5 consists of a concave meniscus lens L14 with a convex surface facing the image side. The sixth lens group G6 consists of a biconvex lens L15.

Figure 81 is a lens configuration diagram of an imaging optical system according to the sixth embodiment of the present invention.

The imaging optical system of Example 6 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. When changing magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image surface. The fourth lens group G4 is a focusing lens group GF, and moves along the optical axis toward the image surface when focusing from an object at infinity to an object at a close distance. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a cemented lens of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and an aspheric R1 surface, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image surface side. The third lens group G3 is composed of a biconvex lens L7 with both R1 and R2 surfaces aspheric, a cemented lens of a biconcave lens L8 and a convex meniscus lens L9 with a convex surface facing the object side, and a biconvex lens L10 with both R1 and R2 surfaces aspheric. The biconvex lens L10 is an anti-vibration lens group GS, and moves with a component perpendicular to the optical axis during anti-vibration. The fourth lens group G4 is composed of a concave meniscus lens L11 with a convex surface facing the object side. The fifth lens group G5 consists of a concave meniscus lens L12 with a convex surface facing the image side. The sixth lens group G6 consists of a convex meniscus lens L13 with a convex surface facing the image side.

Figure 97 is a lens configuration diagram of the imaging optical system according to the seventh embodiment of the present invention.

The imaging optical system of Example 7 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power; when varying the magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image plane. The fourth lens group G4 is a focusing lens group GF, and moves along the optical axis toward the image surface when focusing from an object at infinity to an object at a close distance. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a cemented lens of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and an aspheric R1 surface, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image surface side. The third lens group G3 is composed of a biconvex lens L7 with both R1 and R2 surfaces aspheric, a cemented lens of a biconcave lens L8 and a convex meniscus lens L9 with a convex surface facing the object side, and a biconvex lens L10 with both R1 and R2 surfaces aspheric. The biconvex lens L10 is an anti-vibration lens group GS, and moves with a component perpendicular to the optical axis during anti-vibration. The fourth lens group G4 is composed of a concave meniscus lens L11 with a convex surface facing the object side. The fifth lens group G5 consists of a concave meniscus lens L12 with a convex surface facing the image side. The sixth lens group G6 consists of a convex meniscus lens L13 with a convex surface facing the image side.

Figure 113 is a lens configuration diagram of the imaging optical system according to the eighth embodiment of the present invention.

The imaging optical system of Example 8 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. When changing magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image surface. The fourth lens group G4 is a focusing lens group GF, and moves along the optical axis toward the image surface when focusing from an object at infinity to an object at a close distance. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a cemented lens of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and an aspheric R1 surface, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image surface side. The third lens group G3 is composed of a biconvex lens L7 with both R1 and R2 surfaces aspheric, a cemented lens of a concave meniscus lens L8 with a convex surface facing the object side and a convex meniscus lens L9 with a convex surface facing the object side, and a biconvex lens L10 with both R1 and R2 surfaces aspheric. The biconvex lens L10 is an anti-vibration lens group GS, and moves with a component perpendicular to the optical axis during anti-vibration. The fourth lens group G4 is composed of a concave meniscus lens L11 with a convex surface facing the object side. The fifth lens group G5 consists of a concave meniscus lens L12 with a convex surface facing the image side. The sixth lens group G6 consists of a convex meniscus lens L13 with a convex surface facing the image side.

Figure 129 is a lens configuration diagram of the imaging optical system according to the ninth embodiment of the present invention.

The imaging optical system of Example 9 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. When changing magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image surface. The fourth lens group G4 is a focusing lens group GF, and moves along the optical axis toward the image surface when focusing from an object at infinity to an object at a close distance. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a cemented lens of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and an aspheric R1 surface, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image surface side. The third lens group G3 is composed of a biconvex lens L7 with both R1 and R2 surfaces aspheric, a cemented lens of a concave meniscus lens L8 with a convex surface facing the object side and a convex meniscus lens L9 with a convex surface facing the object side, a cemented lens of a biconcave lens L10 and a convex meniscus lens L11 with a convex surface facing the object side, and a biconvex lens L12 with both R1 and R2 surfaces aspheric. The biconvex lens L12 is an anti-vibration lens group GS, and moves with a component perpendicular to the optical axis during anti-vibration. The fourth lens group G4 is made up of a concave meniscus lens L13 with a convex surface facing the object side. The fifth lens group G5 is made up of a concave meniscus lens L14 with a convex surface facing the image side. The sixth lens group G6 is made up of a convex meniscus lens L15 with a convex surface facing the object side.

Figure 145 shows the lens configuration of the imaging optical system according to the tenth embodiment of the present invention.

The imaging optical system of Example 10 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power; when varying the magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image surface. The fourth lens group G4 is a focusing lens group GF, and moves along the optical axis toward the image surface when focusing from an object at infinity to an object at a close distance. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a cemented lens of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and both R1 and R2 surfaces being aspheric, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image surface side. The third lens group G3 is composed of a biconvex lens L7 with both R1 and R2 surfaces being aspheric, a cemented lens of a biconcave lens L8 and a convex meniscus lens L9 with a convex surface facing the object side, and a biconvex lens L10 with both R1 and R2 surfaces being aspheric. The biconvex lens L10 is an anti-vibration lens group GS, and moves with a component perpendicular to the optical axis during anti-vibration. The fourth lens group G4 is composed of a concave meniscus lens L11 with a convex surface facing the object side. The fifth lens group G5 consists of a concave meniscus lens L12 with a convex surface facing the image side. The sixth lens group G6 consists of a convex meniscus lens L13 with a convex surface facing the image side.

Figure 161 shows the lens configuration of the imaging optical system according to the eleventh embodiment of the present invention.

The imaging optical system of Example 11 comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. When changing magnification from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 increases, the third lens group G3 and the fifth lens group G5 move along the same trajectory, and the sixth lens group G6 is fixed with respect to the image surface. The fourth lens group G4 is a focusing lens group GF, which moves toward the object along the optical axis when focusing from an object at infinity to an object at a close distance. The fifth lens group G5 is an anti-vibration lens group GS, which moves with a vertical component along the optical axis when preventing vibration. The rear lens group GR corresponds to the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6.

The first lens group G1 is composed of a cemented lens of a concave meniscus lens L1 with a convex surface facing the object side and a convex meniscus lens L2 with a convex surface facing the object side. The second lens group G2 is composed of a concave meniscus lens L3 with a convex surface facing the object side and both R1 and R2 surfaces being aspheric, a cemented lens of a biconcave lens L4 and a biconvex lens L5, and a concave meniscus lens L6 with a convex surface facing the image side. The third lens group G3 is composed of a biconvex lens L7 with both R1 and R2 surfaces being aspheric, a cemented lens of a concave meniscus lens L8 with a convex surface facing the object side and a convex meniscus lens L9 with a convex surface facing the object side, and a cemented lens of a biconcave lens L10 and a biconvex lens L11. The fourth lens group G4 is composed of a biconvex lens L12 with both R1 and R2 surfaces being aspheric. The fifth lens group G5 is composed of a concave meniscus lens L13 with a convex surface facing the object side. The sixth lens group G6 consists of a biconvex lens L14.

Below is given specific numerical data for each embodiment of the imaging optical system of the present invention described above.

In [Surface Data], the surface number is the lens surface or aperture stop number counted from the object side, r is the radius of curvature of each surface, d is the spacing between each surface, nd is the refractive index for the d line (wavelength 587.56 nm), and vd is the Abbe number for the d line.

An asterisk (*) next to a surface number indicates that the lens surface is aspheric. Also, BF stands for back focus.

The (Aperture) next to a surface number indicates that an aperture stop is located at that position. The radius of curvature for the plane or aperture stop is marked ∞ (infinity).

[Aspheric Data] shows the values of each coefficient that gives the aspheric shape of the lens surfaces marked with an * in [Surface Data]. The shape of the aspheric surface is expressed by the following formula, where y is the displacement from the optical axis in a direction perpendicular to the optical axis, z is the displacement (sag) from the intersection of the aspheric surface and the optical axis in the direction of the optical axis, r is the radius of curvature of the reference sphere, K is the Conic coefficient, and A4, A6, ..., A16 are the fourth-order to **-order aspheric coefficients, respectively.

[Various data] shows values such as zoom ratio and focal length for each focal length state.

[Variable Distance Data] shows the variable distance and BF values for each focal length state.

[Lens group data] shows the surface number of each lens group closest to the object and the composite focal length of the entire group.

In addition, for all the values of the following specifications, the focal length f, radius of curvature r, lens surface spacing d, and other length units are given in millimeters (mm) unless otherwise specified, but this is not limited to this because the optical system provides equivalent optical performance with proportional magnification and proportional reduction.

A list of the corresponding values of the conditional expressions in each of these examples is also provided.

In addition, in the aberration diagrams corresponding to each embodiment, d, g, and C represent the d-line, g-line, and C-line, respectively, and △S and △M represent the sagittal image surface and meridional image surface, respectively.

Numerical Example 1
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 42.4041 0.9000 1.94594 17.98 0.6546
2 31.9285 6.7226 1.80420 46.50 0.5573
3 222.8493 (d3)
4* 108.9547 1.3340 1.80610 40.73 0.5694
5 13.0391 5.4197
6 -30.0939 1.8955 1.61340 44.27 0.5633
7 17.2404 3.7808 1.92119 23.96 0.6202
8 -100.0838 2.5950
9 -16.3540 0.9000 1.87070 40.73 0.5682
10 -24.6204 (d10)
11(Aperture) ∞ 1.2000
12* 19.8492 5.4945 1.77250 49.50 0.5519
13* -60.0349 0.3826
14 -366.2956 1.8682 1.77047 29.74 0.5951
15 14.2993 3.4620 1.49700 81.61 0.5389
16 34.2759 3.1228
17* 24.2253 5.1628 1.59271 66.97 0.5367
18* -22.4374 (d18)
19 61.8773 0.9000 1.74330 49.22 0.5495
20 21.4587 (d20)
21 -256.7002 0.8000 1.62004 36.30 0.5873
22 237.6414 (d22)
23 326.6251 3.2840 1.72916 54.67 0.5453
24 -58.3586 (BF)
Image plane ∞

[Aspheric data]
4th floor 12th floor 13th floor 17th floor 18th floor
K 0.0000 0.0000 0.0000 0.0000 0.0000
A4 1.55138E-05 -1.83238E-05 1.19464E-05 -2.39839E-05 3.08287E-05
A6 -1.04404E-07 -8.34593E-09 -1.73604E-08 1.85323E-08 -1.24805E-08
A8 1.57103E-09 -9.45349E-11 3.97624E-09 7.05415E-09 -1.48225E-09
A10 -1.42124E-11 -4.14960E-11 -2.39721E-10 -1.30039E-10 2.62402E-10
A12 7.07326E-14 5.82724E-13 4.39804E-12 7.94872E-13 -7.00142E-12
A14 -1.39865E-16 -3.69214E-15 -3.87616E-14 8.64117E-15 8.43479E-14
A16 0.00000E+00 0.00000E+00 1.26022E-16 -8.15382E-17 -3.71725E-16

[Various data]
Zoom ratio 2.61
Wide Angle Mid Telephoto Focal Length 18.60 30.00 48.50
F-number 2.92 2.92 2.92
Full angle of view 2ω 79.04 49.46 31.24
Image height Y 14.20 14.20 14.20
Lens length 91.81 98.14 114.15

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d3 1.2000 9.2981 18.0093
d10 12.5745 4.9764 1.7000
d18 1.6500 3.6748 1.9507
d20 8.7323 6.7075 8.4316
d22 0.7827 6.6120 17.1831
BF 17.6476 17.6476 17.6476

Wide Angle Mid-Telephoto
d0 721.9425 1164.3501 1883.2288
d3 1.2000 9.2981 18.0093
d10 12.5745 4.9764 1.7000
d18 1.9867 4.1475 2.4658
d20 8.3956 6.2348 7.9166
d22 0.7827 6.6120 17.1831
BF 17.6476 17.6476 17.6476

[Lens group data]
Group starting plane focal length
G1 1 68.57
G2 4 -14.63
G3 12 18.95
G4 19 -44.62
G5 21 -198.90
G6 23 68.15

Numerical Example 2
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 38.7099 0.9000 1.94594 17.98 0.6546
2 27.7773 7.4568 1.83481 42.72 0.5647
3 179.7754 (d3)
4* 122.8167 1.3418 1.85135 40.10 0.5695
5 12.9020 5.1695
6 -31.2112 0.8000 1.61340 44.27 0.5633
7 15.6260 4.3245 1.92119 23.96 0.6202
8 -102.5099 2.3934
9 -15.6694 0.9000 1.88300 40.81 0.5656
10 -24.3331 (d10)
11(Aperture) ∞ 1.1000
12* 18.0948 5.1486 1.77250 49.50 0.5519
13* -61.8421 0.3000
14 402.3842 0.9000 1.77047 29.74 0.5951
15 13.2883 3.3499 1.49700 81.61 0.5389
16 23.3742 3.9682
17* 19.7038 6.0680 1.59271 66.97 0.5367
18* -21.7445 (d18)
19 64.8045 0.9000 1.74330 49.22 0.5495
20 19.5913 (d20)
21 -185.5740 0.8000 1.72825 28.32 0.6059
22 308.1656 (d22)
23 308.1656 4.0958 1.61997 63.88 0.5426
24 -42.6690 (BF)
Image plane ∞

[Aspheric data]
4th floor 12th floor 13th floor 17th floor 18th floor
K 0.0000 0.0000 0.0000 0.0000 0.0000
A4 1.47109E-05 -2.53421E-05 6.79565E-06 -3.88113E-05 3.61927E-05
A6 -7.08372E-08 -2.90336E-08 6.55692E-09 5.82013E-08 -7.39857E-09
A8 7.97362E-10 5.50493E-10 4.61921E-09 1.24861E-09 -4.70623E-09
A10 -5.03414E-12 -3.84489E-11 -2.21040E-10 4.28091E-11 3.10776E-10
A12 2.04962E-14 3.25848E-13 3.64982E-12 -1.24889E-12 -6.39658E-12
A14 -3.51721E-17 -2.47441E-15 -3.31914E-14 1.38691E-14 6.29811E-14
A16 0.00000E+00 0.00000E+00 1.17190E-16 -4.81520E-17 -2.34532E-16

[Various data]
Zoom ratio 2.61
Wide Angle Mid Telephoto Focal Length 18.60 30.00 48.50
F-number 2.92 2.92 2.92
Full angle of view 2ω 79.70 49.68 31.55
Image height Y 14.20 14.20 14.20
Lens length 89.31 95.22 110.47

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d3 1.1000 8.5574 15.3066
d10 11.6421 4.6847 1.6000
d18 1.5000 3.2600 1.7491
d20 7.4720 5.7120 7.2229
d22 0.7000 6.1169 17.6950
BF 16.9770 16.9770 16.9770

Wide Angle Mid-Telephoto
d0 721.3487 1163.3021 1886.3109
d3 1.1000 8.5574 15.3066
d10 11.6421 4.6847 1.6000
d18 1.7933 3.6714 2.1775
d20 7.1787 5.3006 6.7945
d22 0.7000 6.1169 17.6950
BF 16.9770 16.9770 16.9770

[Lens group data]
Group starting plane focal length
G1 1 61.44
G2 4 -13.52
G3 12 17.97
G4 19 -38.10
G5 21 -158.94
G6 23 60.73

Numerical Example 3
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 46.5648 0.9000 1.94594 17.98 0.6546
2 35.7311 6.0969 1.77250 49.63 0.5504
3 289.7975 (d3)
4* 84.0931 1.3142 1.85108 40.12 0.5685
5 13.4448 5.4605
6 -33.7847 0.8000 1.61340 44.27 0.5633
7 15.8729 4.5546 1.92119 23.96 0.6202
8 -134.9879 2.6848
9 -15.8601 0.9000 1.90043 37.37 0.5767
10 -22.7317 (d10)
11 (Aperture) ∞ 0.7000
12* 18.2080 5.3697 1.80610 40.73 0.5694
13* -68.3430 0.5222
14 -162.4046 0.9000 1.78880 28.43 0.6009
15 12.6129 3.9665 1.49700 81.61 0.5389
16 29.8567 3.3062
17* 19.4939 6.4127 1.59271 66.97 0.5367
18* -21.2236 (d18)
19 77.5014 0.9000 1.74330 49.22 0.5495
20 19.5283 (d20)
21 -127.7080 0.8000 1.51742 52.15 0.5590
22 963.7790 (d22)
23 1999.4385 3.4394 1.72916 54.67 0.5453
24 -49.1054 (BF)
Image plane ∞

[Aspheric data]
4th floor 12th floor 13th floor 17th floor 18th floor
K 0.0000 0.0000 0.0000 0.0000 0.0000
A4 1.09556E-05 -1.83199E-05 7.97168E-07 -5.46727E-05 2.75178E-05
A6 -4.86675E-08 -3.90825E-08 5.14262E-08 6.30329E-08 -2.99365E-08
A8 5.36044E-10 -1.28019E-09 -1.16467E-09 9.99159E-10 -1.63126E-09
A10 -2.31014E-12 4.27345E-11 3.38823E-11 -3.07799E-11 5.07271E-11
A12 5.07917E-15 -6.84118E-13 -7.60525E-13 3.74100E-13 -4.99493E-13
A14 -3.40374E-19 2.59480E-15 3.73749E-15 -1.88342E-15 1.43682E-15
A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

[Various data]
Zoom ratio 2.64
Wide Angle Mid Telephoto Focal Length 18.43 30.00 48.60
F-number 2.91 2.91 2.91
Full angle of view 2ω 79.11 49.30 31.10
Image height Y 14.20 14.20 14.20
Lens length 92.51 98.96 116.50

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d3 1.2000 10.1968 20.4811
d10 14.0492 5.5608 2.3000
d18 1.5000 3.4667 2.2789
d20 8.0322 6.0655 7.2533
d22 0.9258 6.8771 17.3889
BF 17.7700 17.7700 17.7700

Wide Angle Mid-Telephoto
d0 715.5048 1164.1578 1883.6933
d3 1.2000 10.1968 20.4811
d10 14.0492 5.5608 2.3000
d18 1.7549 3.8244 2.6738
d20 7.7773 5.7078 6.8584
d22 0.9258 6.8771 17.3889
BF 17.7700 17.7700 17.7700

[Lens group data]
Group starting plane focal length
G1 1 76.88
G2 4 -15.45
G3 12 18.57
G4 19 -35.36
G5 21 -217.88
G6 23 65.78

Numerical Example 4
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 43.4100 0.9000 1.86966 20.02 0.6435
2 32.4307 0.6328
3 33.8907 6.5282 1.72916 54.67 0.5453
4 580.3566 (d4)
5* 207.9330 1.3181 1.80610 40.73 0.5694
6 13.5717 4.8232
7 -35.7070 0.8000 1.71300 53.94 0.5442
8 15.7972 4.4839 2.00100 29.13 0.5995
9 -70.4523 2.1559
10 -16.9410 0.9000 1.87070 40.73 0.5682
11 -29.2149 (d11)
12 (Aperture) ∞ 0.8874
13* 22.1365 4.9114 1.77250 49.50 0.5519
14* 232.1269 1.9942
15 389.4081 2.2175 1.77047 29.74 0.5951
16 17.4722 4.2155 1.49700 81.61 0.5389
17 -599.1015 2.1886
18* 19.9534 5.4749 1.59271 66.97 0.5367
19* -22.3009 (d19)
20 47.4022 0.9000 1.77250 49.63 0.5504
21 16.6455 (d21)
22 -24.4824 0.8000 1.69895 30.05 0.6029
23 -34.7615 (d23)
24 -601.7493 3.4696 1.72916 54.67 0.5453
25 -43.4690 (BF)
Image plane ∞

[Aspheric data]
5th 13th 14th 18th 19th
K 0.0000 0.0000 0.0000 0.0000 0.0000
A4 1.34100E-05 -1.22802E-05 5.58308E-06 -3.81779E-05 3.59404E-05
A6 -5.46748E-08 -2.89981E-09 -4.29555E-09 7.63292E-09 -7.29156E-08
A8 9.80885E-10 -9.46761E-10 1.56662E-09 2.14471E-09 2.25395E-09
A10 -9.08454E-12 -2.20701E-13 -6.83314E-11 -2.61470E-11 -2.20867E-11
A12 4.51659E-14 -1.83799E-13 4.66831E-13 1.81132E-13 2.03146E-13
A14 -8.75546E-17 1.14926E-15 -1.13843E-15 3.89340E-16 4.88692E-17
A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

[Various data]
Zoom ratio 2.64
Wide Angle Mid Telephoto Focal Length 18.43 30.00 48.60
F-number 2.91 2.91 2.91
Full angle of view 2ω 80.48 50.11 31.10
Image height Y 14.20 14.20 14.20
Lens length 93.51 99.59 114.42

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d4 1.1000 8.0498 20.1119
d11 13.5610 5.2304 1.6000
d19 1.5000 3.1046 2.9353
d21 10.0927 8.4882 8.6574
d23 0.7000 8.1692 14.5681
BF 16.9500 16.9500 16.9500

Wide Angle Mid-Telephoto
d0 714.6167 1167.9033 1882.8604
d4 1.1000 8.0498 20.1119
d11 13.5610 5.2304 1.6000
d19 1.7117 3.3795 3.2912
d21 9.8811 8.2132 8.3015
d23 0.7000 8.1692 14.5681
BF 16.9500 16.9500 16.9500

[Lens group data]
Group starting plane focal length
G1 1 73.03
G2 5 -14.82
G3 13 17.63
G4 20 -33.64
G5 22 -122.37
G6 24 64.09

Numerical Example 5
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 42.7613 1.0000 1.84666 23.78 0.6192
2 28.3716 7.1064 1.77250 49.63 0.5504
3 207.0596 (d3)
4* 126.7118 1.1935 1.80834 40.92 0.5686
5 12.0127 5.1318
6 -24.6490 0.8000 1.60342 38.01 0.5828
7 16.6349 3.8669 1.92119 23.96 0.6202
8 -51.8156 2.1955
9 -15.3504 0.8000 1.90043 37.37 0.5767
10 -22.0583 (d10)
11(Aperture) ∞ 1.0000
12* 15.1373 5.0229 1.80610 40.73 0.5694
13* -78.3037 0.1500
14 -2724.7673 0.8000 1.91082 35.25 0.5822
15 9.5419 4.2273 1.59282 68.62 0.5440
16 59.3243 2.8007
17 -14.5033 0.8000 1.77047 29.74 0.5951
18 -20.4247 0.1500
19 -50.1254 2.6915 1.59282 68.62 0.5440
20 -17.0854 0.3000
21* 24.0310 3.8640 1.59201 67.02 0.5358
22* -38.9163 (d22)
23 54.2639 0.8000 1.77250 49.63 0.5504
24 18.0643 (d24)
25 -47.6946 0.8000 1.85451 25.15 0.6103
26 -92.5624 (d26)
27 115.5641 3.2861 1.83481 42.72 0.5647
28 -78.2968 (BF)
Image plane ∞

[Aspheric data]
4th floor 12th floor 13th floor 21st floor 22nd floor
K 0.0000 0.0000 0.0000 0.0000 0.0000
A4 2.45639E-05 -1.04130E-05 3.50387E-05 -4.02921E-06 2.48979E-05
A6 -9.13609E-08 9.12741E-08 -4.47768E-08 -3.43621E-07 -3.56903E-07
A8 9.69870E-10 -1.21273E-09 7.82874E-10 6.79289E-09 5.55995E-09
A10 -5.58581E-12 1.47600E-11 -1.71711E-11 -8.36158E-11 -6.13618E-11
A12 1.71809E-14 -9.71183E-14 5.71635E-14 3.66285E-13 2.29766E-13
A14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

[Various data]
Zoom ratio 2.63
Wide Angle Mid Telephoto Focal Length 18.45 29.93 48.55
F-number 2.91 2.91 2.91
Full angle of view 2ω 78.31 49.45 31.13
Image height Y 14.20 14.20 14.20
Lens length 90.42 97.86 113.92

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d3 1.2000 10.6954 20.7097
d10 12.3120 4.6364 1.3275
d22 1.5000 3.1929 2.2863
d24 7.9458 6.2529 7.1594
d26 1.2000 6.8234 16.1698
BF 17.4771 17.4771 17.4771

Wide Angle Mid-Telephoto
d0 717.1439 1159.5500 1878.5881
d3 1.2000 10.6954 20.7097
d10 12.3120 4.6364 1.3275
d22 1.7518 3.5466 2.6926
d24 7.6939 5.8992 6.7532
d26 1.2000 6.8234 16.1698
BF 17.4771 17.4771 17.4771

[Lens group data]
Group starting plane focal length
G1 1 72.57
G2 4 -15.11
G3 12 18.25
G4 23 -35.39
G5 25 -116.10
G6 27 56.34

Numerical Example 6
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 40.9106 0.9000 1.94594 17.98 0.6546
2 32.5085 6.3473 1.72916 54.67 0.5453
3 238.6818 (d3)
4* 68.2047 1.2354 1.85108 40.12 0.5685
5 12.7563 4.9932
6 -36.4994 0.9544 1.65412 39.68 0.5737
7 13.9645 4.2330 1.92119 23.96 0.6202
8 -155.6530 2.1375
9 -15.1681 0.9000 1.88300 40.81 0.5656
10 -22.5605 (d10)
11 (Aperture) ∞ 0.7000
12* 18.4908 4.1322 1.80610 40.73 0.5694
13* -43.8045 0.6117
14 -88.7294 0.9000 1.78880 28.43 0.6009
15 13.4237 2.2783 1.49700 81.61 0.5389
16 28.1058 2.0004
17* 24.9939 6.7279 1.59271 66.97 0.5367
18* -15.9379 (d18)
19 53.7143 0.9000 1.74330 49.22 0.5495
20 19.0461 (d20)
21 -66.2055 0.8000 1.72342 37.99 0.5820
22 -673.6734 (d22)
23 -673.6734 3.2218 1.72916 54.67 0.5453
24 -47.8641 (BF)
Image plane ∞

[Aspheric data]
4th floor 12th floor 13th floor 17th floor 18th floor
K 0.0000 0.0000 0.0000 0.0000 0.0000
A4 7.51456E-06 -3.53436E-05 -4.92927E-06 -7.92987E-05 2.16492E-05
A6 -5.22798E-08 -8.36824E-08 8.54305E-08 2.12265E-07 -2.54911E-08
A8 1.13546E-09 -2.96526E-08 -3.91809E-08 -2.78117E-08 -1.47062E-08
A10 -9.22403E-12 1.12610E-09 1.49017E-09 1.06611E-09 4.93766E-10
A12 3.93488E-14 -2.50805E-11 -3.32080E-11 -2.10093E-11 -8.16624E-12
A14 -5.57775E-17 1.73706E-13 2.48746E-13 1.48680E-13 4.67402E-14
A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

[Various data]
Zoom ratio 2.90
Wide Angle Mid Telephoto Focal Length 18.43 29.97 53.40
F-number 2.91 3.24 4.00
Full angle of view 2ω 80.50 49.48 28.42
Image height Y 14.20 14.20 14.20
Lens length 85.00 90.07 110.00

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d3 1.1000 9.5769 21.3188
d10 12.5981 4.6212 1.5000
d18 1.5000 4.1322 2.2053
d20 8.6948 6.0626 7.9895
d22 0.7000 5.2650 16.5750
BF 16.4386 16.4386 16.4386

Wide Angle Mid-Telephoto
d0 716.6458 1164.4161 2074.3623
d3 1.1000 9.5769 21.3188
d10 12.5981 4.6212 1.5000
d18 1.7704 4.5389 2.6465
d20 8.4243 5.6559 7.5483
d22 0.7000 5.2650 16.5750
BF 16.4386 16.4386 16.4386

[Lens group data]
Group starting plane focal length
G1 1 73.06
G2 4 -14.44
G3 12 16.74
G4 19 -40.15
G5 21 -101.55
G6 23 70.51

Numerical Example 7
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 45.0587 0.9000 1.94594 17.98 0.6546
2 34.2015 6.2370 1.77250 49.63 0.5504
3 335.3946 (d3)
4* 164.9172 1.3419 1.85108 40.12 0.5685
5 12.5924 5.2058
6 -26.9164 1.0336 1.61340 44.27 0.5633
7 15.5763 4.1894 1.92119 23.96 0.6202
8 -65.2765 2.2680
9 -15.6955 0.9000 1.90366 31.32 0.5948
10 -23.9531 (d10)
11 (Aperture) ∞ 0.7000
12* 20.5700 6.6201 1.80610 40.73 0.5694
13* -43.9573 0.4521
14 -96.7320 0.9000 1.78880 28.43 0.6009
15 13.4697 3.5547 1.49700 81.61 0.5389
16 45.4566 3.4380
17* 18.7696 5.1297 1.59271 66.97 0.5367
18* -18.1920 (d18)
19 44.6598 0.9000 1.74330 49.22 0.5495
20 16.0741 (d20)
21 -50.0564 0.8000 1.63980 34.46 0.5922
22 -326.8622 (d22)
23 -326.8622 3.9479 1.71300 53.94 0.5442
24 -35.8637 (BF)
Image plane ∞

[Aspheric data]
4th floor 12th floor 13th floor 17th floor 18th floor
K 0.0000 0.0000 0.0000 0.0000 0.0000
A4 1.79255E-05 -3.31671E-05 -4.71774E-06 -5.55551E-05 5.03028E-05
A6 -8.33196E-08 -4.56723E-08 -7.79680E-09 1.04802E-07 -4.60324E-08
A8 8.84215E-10 -4.48987E-09 -2.87659E-09 -2.44960E-09 -4.40088E-09
A10 -6.02608E-12 3.75379E-11 -2.86739E-11 1.42128E-10 2.33034E-10
A12 2.82558E-14 -2.09838E-13 5.21513E-13 -2.46080E-12 -3.66978E-12
A14 -6.29490E-17 -2.40131E-15 -4.20155E-15 1.77886E-14 2.37909E-14
A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
[Various data]
Zoom ratio 2.39
Wide Angle Mid Telephoto Focal Length 16.30 26.60 38.99
F-number 2.91 2.91 2.91
Full angle of view 2ω 87.23 54.82 38.26
Image height Y 14.20 14.20 14.20
Lens length 85.01 92.49 106.84

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d3 1.1000 8.7539 16.7477
d10 10.5289 3.3750 1.5000
d18 1.5000 2.8910 1.8780
d20 6.6578 5.2668 6.2799
d22 0.7000 7.6877 15.9127
BF 16.0000 16.0000 16.0000

Wide Angle Mid-Telephoto
d0 632.2673 1032.0634 1508.5486
d3 1.1000 8.7539 16.7477
d10 10.5289 3.3750 1.5000
d18 1.7269 3.1831 2.1811
d20 6.4309 4.9748 5.9768
d22 0.7000 7.6877 15.9127
BF 16.0000 16.0000 16.0000

[Lens group data]
Group starting plane focal length
G1 1 72.36
G2 4 -13.65
G3 12 16.61
G4 19 -34.25
G5 21 -92.49
G6 23 56.18

Numerical Example 8
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 47.3193 0.9000 1.94594 17.98 0.6546
2 32.9545 5.9764 1.83481 42.72 0.5647
3 292.4944 (d3)
4* 78.8083 1.5002 1.85135 40.10 0.5695
5 12.6302 4.9783
6 -32.0456 0.8000 1.61772 49.81 0.5603
7 15.8713 3.7025 2.00069 25.46 0.6136
8 -182.2260 2.1160
9 -15.6736 0.9000 1.88300 40.81 0.5656
10 -25.2274 (d10)
11 (Aperture) ∞ 1.2435
12* 14.5899 3.4404 1.76450 49.09 0.5528
13* -80.6288 0.6467
14 201.4155 0.9000 1.77047 29.74 0.5951
15 11.7218 2.0475 1.49700 81.61 0.5389
16 17.4576 3.3173
17* 19.0871 3.8521 1.59271 66.97 0.5367
18* -19.5405 (d18)
19 54.6628 0.9000 1.74330 49.22 0.5495
20 18.1271 (d20)
21 -97.6591 0.8000 1.68960 31.14 0.6031
22 -1407.9599 (d22)
23 -1407.9599 3.9263 1.59349 67.00 0.5366
24 -38.9570 (BF)
Image plane ∞

[Aspheric data]
4th floor 12th floor 13th floor 17th floor 18th floor
K 0.0000 0.0000 0.0000 0.0000 0.0000
A4 1.09444E-05 -1.84356E-05 4.56496E-05 -1.68807E-05 6.52329E-05
A6 -6.69600E-08 -1.35031E-07 -1.63343E-07 1.21303E-07 1.31835E-07
A8 1.34781E-09 -1.65708E-08 -1.04944E-08 2.07191E-08 4.19673E-09
A10 -1.43692E-11 1.35463E-09 2.44899E-10 -8.32610E-10 4.72454E-10
A12 8.46626E-14 -4.36325E-11 1.42345E-11 2.86110E-11 -1.24750E-11
A14 -1.90066E-16 4.33331E-13 -9.97512E-13 -5.02824E-13 1.39908E-13
A16 0.00000E+00 0.00000E+00 1.36724E-14 4.42223E-15 4.28251E-16

[Various data]
Zoom ratio 2.78
Wide Angle Mid Telephoto Focal Length 17.45 30.00 48.50
F-number 4.11 4.11 4.10
Full angle of view 2ω 83.61 49.41 31.16
Image height Y 14.20 14.20 14.20
Lens length 80.01 88.14 105.10

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d3 1.1000 9.1535 19.3271
d10 11.7350 4.1815 1.6000
d18 1.5000 2.9328 1.5388
d20 7.0082 5.5754 6.9694
d22 0.7000 8.3288 17.6950
BF 16.0228 16.0228 16.0228

Wide Angle Mid-Telephoto
d0 678.2172 1168.5611 1886.6521
d3 1.1000 9.1535 19.3271
d10 11.7350 4.1815 1.6000
d18 1.7673 3.2889 1.9332
d20 6.7409 5.2193 6.5750
d22 0.7000 8.3288 17.6950
BF 16.0228 16.0228 16.0228

[Lens group data]
Group starting plane focal length
G1 1 71.55
G2 4 -14.12
G3 12 16.10
G4 19 -36.87
G5 21 -152.21
G6 23 67.44

Numerical Example 9
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 68.3850 1.0000 1.86966 20.02 0.6435
2 48.1024 6.1633 1.77250 49.63 0.5504
3 680.1174 (d3)
4* 68.2033 1.1801 1.80834 40.92 0.5686
5 17.0141 7.2775
6 -35.0918 1.3688 1.65100 56.24 0.5420
7 21.0420 5.0717 1.90366 31.32 0.5948
8 -61.2061 2.9974
9 -19.2183 0.8000 1.80420 46.50 0.5573
10 -30.3720 (d10)
11(Aperture) ∞ 1.0000
12* 37.6860 3.0587 1.69350 53.20 0.5467
13* -2438.4624 1.8851
14 17.2305 2.0825 1.80610 33.27 0.5884
15 11.8961 5.6910 1.49700 81.61 0.5389
16 20.8384 2.8749
17 -180.6181 0.8000 1.80518 25.46 0.6157
18 51.9360 1.9468 1.59410 60.47 0.5552
19 264.1760 6.2729
20* 22.0907 6.5757 1.59201 67.02 0.5358
21* -29.3796 (d21)
22 38.5734 1.6098 1.77250 49.63 0.5504
23 19.6167 (d23)
24 -52.2008 0.8000 1.74330 49.22 0.5495
25 -335.5406 (d25)
26 36.0191 3.1092 1.72916 54.67 0.5453
27 85.1538 (BF)
Image plane ∞

[Aspheric data]
4th floor 12th floor 13th floor 20th floor 21st floor
K 0.0000 0.0000 0.0000 0.0000 0.0000
A4 8.08447E-06 -1.99450E-07 4.22345E-06 -2.57460E-05 1.58700E-05
A6 -6.17604E-09 1.48957E-07 1.46438E-07 -4.48514E-08 -7.04011E-08
A8 1.28195E-10 -1.16599E-09 -1.02202E-09 5.44365E-10 6.84669E-10
A10 -5.05057E-13 8.63302E-12 7.89701E-12 -4.13181E-12 -4.77526E-12
A12 1.38114E-15 -2.99096E-14 -3.03193E-14 8.33713E-15 1.02190E-14
A14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

[Various data]
Zoom ratio 2.90
Wide Angle Mid Telephoto Focal Length 23.45 39.96 68.00
F-number 2.91 2.91 2.91
Full angle of view 2ω 63.77 37.75 22.74
Image height Y 14.20 14.20 14.20
Lens length 115.01 129.53 144.79

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d3 1.2000 18.9606 30.3005
d10 20.1294 9.6598 1.0000
d21 1.5000 2.2789 2.2460
d23 10.6051 9.8263 9.8591
d25 1.2000 8.4324 21.0131
BF 16.8071 16.8071 16.8071

Wide Angle Mid-Telephoto
d0 909.3184 1534.9113 2632.3270
d3 1.2000 18.9606 30.3005
d10 20.1294 9.6598 1.0000
d21 1.9150 2.8309 2.8701
d23 10.1902 9.2742 9.2350
d25 1.2000 8.4324 21.0131
BF 16.8071 16.8071 16.8071

[Lens group data]
Group starting plane focal length
G1 1 103.89
G2 4 -22.85
G3 12 26.55
G4 22 -53.66
G5 24 -83.27
G6 26 83.39

Numerical Example 10
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 72.5450 0.9000 1.92119 23.96 0.6202
2 44.3709 10.2066 1.80420 46.50 0.5573
3 564.1764 (d3)
4* 109.9354 1.2547 1.76802 49.24 0.5516
5* 21.8194 8.2519
6 -37.9444 2.7527 1.61340 44.27 0.5633
7 30.5441 5.6302 1.92119 23.96 0.6202
8 -167.8832 3.2605
9 -24.2469 1.8929 1.88300 40.81 0.5656
10 -36.7191 (d10)
11(Aperture) ∞ 1.2000
12* 30.3692 8.6351 1.77250 49.46 0.5539
13* -73.2042 0.3000
14 -545.3813 1.9918 1.77047 29.74 0.5951
15 22.8002 9.2574 1.49700 81.61 0.5389
16 39.9538 4.6338
17* 26.6904 8.9325 1.59271 66.97 0.5367
18* -35.3661 (d18)
19 56.3961 1.4906 1.74330 49.22 0.5495
20 24.6219 (d20)
21 -40.0095 0.8000 1.77047 29.74 0.5951
22 -61.5572 (d22)
23 -222.3949 3.5658 1.72916 54.67 0.5453
24 -58.9876 (BF)
Image plane ∞

[Aspheric data]
4th 5th 12th
K 0.0000 0.0000 0.0000
A4 4.47410E-06 1.05434E-06 -8.83945E-06
A6 3.04043E-08 5.50469E-08 1.98321E-09
A8 -2.97646E-10 -3.86316E-10 -2.21611E-10
A10 1.50325E-12 1.38347E-12 2.72965E-13
A12 -3.51504E-15 0.00000E+00 3.20189E-15
A14 3.33552E-18 0.00000E+00 -2.41573E-17
A16 0.00000E+00 0.00000E+00 0.00000E+00
13th 17th 18th
K 0.0000 0.0000 0.0000
A4 -9.75754E-07 -1.08381E-05 1.20429E-05
A6 3.10826E-09 2.26793E-09 -7.41889E-09
A8 -1.19123E-10 1.85468E-10 1.05883E-10
A10 -2.08756E-12 8.70142E-13 3.61538E-12
A12 2.52768E-14 -1.46025E-14 -3.76078E-14
A14 -1.29845E-16 7.67060E-17 1.60011E-16
A16 2.15945E-19 -7.86897E-20 -1.51918E-19

[Various data]
Zoom ratio 2.55
Wide Angle Mid Telephoto Focal Length 28.50 45.00 72.80
F-number 2.92 2.92 2.92
Full angle of view 2ω 79.08 50.25 31.60
Image height Y 21.63 21.63 21.63
Lens length 135.24 145.97 165.37

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d3 1.1000 14.0555 29.1370
d10 19.0721 8.3778 1.7000
d18 1.5000 3.5415 3.5473
d20 15.2839 13.2424 13.2366
d22 0.7000 9.1682 20.1606
BF 22.6296 22.6296 22.6296

Wide Angle Mid-Telephoto
d0 1105.9598 1745.9645 2820.8243
d3 1.1000 14.0555 29.1370
d10 19.0721 8.3778 1.7000
d18 1.9256 4.0951 4.2201
d20 14.8584 12.6888 12.5638
d22 0.7000 9.1682 20.1606
BF 22.6296 22.6296 22.6296

[Lens group data]
Group starting plane focal length
G1 1 114.40
G2 4 -22.99
G3 12 27.61
G4 19 -59.99
G5 21 -150.79
G6 23 109.10

Numerical Example 11
Unit: mm
[Face data]
Surface number rd nd vd PgF
Object surface ∞ (d0)
1 38.0857 1.0000 1.80809 22.76 0.6287
2 27.4246 6.3831 1.72916 54.67 0.5453
3 194.6484 (d3)
4* 69.8716 1.1721 1.80834 40.92 0.5686
5 12.0574 5.4022
6 -26.3242 1.0073 1.70154 41.15 0.5770
7 16.3988 4.0708 2.00069 25.46 0.6136
8 -56.4419 2.1190
9 -15.6041 0.8000 1.90043 37.37 0.5767
10 -24.9569 (d10)
11 (Aperture) ∞ 0.9663
12* 29.6609 2.8717 1.76802 49.24 0.5516
13* -92.1828 0.5000
14 17.4344 1.1880 1.73037 32.23 0.5899
15 10.8271 2.9535 1.55032 75.50 0.5401
16 16.1215 2.5920
17 -122.8295 0.8000 1.85451 25.15 0.6103
18 54.1065 2.7130 1.59282 68.62 0.5440
19 -41.2347 (d19)
20* 27.6453 4.5453 1.59201 67.02 0.5358
21* -31.2090 (d21)
22 236.9888 0.8000 1.74330 49.22 0.5495
23 21.5280 (d23)
24 53.8093 5.2286 1.48749 70.44 0.5306
25 -56.2838 (BF)
Image plane ∞

[Aspheric data]
4th floor 12th floor 13th floor 20th floor 21st floor
K 0.0000 0.0000 0.0000 0.0000 0.0000
A4 1.45836E-05 5.37165E-06 2.14026E-05 -1.38031E-05 1.11833E-05
A6 7.95635E-09 -1.20066E-07 -1.50610E-07 3.37316E-08 5.75401E-08
A8 -1.29993E-10 2.78394E-09 3.14625E-09 -3.63190E-10 -1.02947E-09
A10 1.36888E-12 -1.85033E-11 -2.09938E-11 1.98358E-12 5.05012E-12
A12 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
A14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

[Various data]
Zoom ratio 2.62
Wide Angle Mid Telephoto Focal Length 18.53 29.83 48.51
F-number 2.91 2.91 2.91
Full angle of view 2ω 78.07 50.44 31.15
Image height Y 14.20 14.20 14.20
Lens length 90.11 93.86 113.20

[Variable interval data]
Wide Angle Mid-Telephoto
d0∞∞∞∞
d3 0.9559 5.9805 18.3147
d10 11.7396 3.5262 1.3308
d19 6.5890 4.0657 5.6305
d21 2.0425 4.5657 3.0010
d23 3.3462 10.2858 19.4931
BF 18.3196 18.3196 18.3196

Wide Angle Mid-Telephoto
d0 721.2976 1171.8515 1892.1010
d3 0.9559 5.9805 18.3147
d10 11.7396 3.5262 1.3308
d19 6.3394 3.7444 5.2160
d21 2.2920 4.8870 3.4155
d23 3.3462 10.2858 19.4931
BF 18.3196 18.3196 18.3196

[Lens group data]
Group starting plane focal length
G1 1 67.00
G2 4 -14.20
G3 12 30.31
G4 20 25.49
G5 22 -31.91
G6 24 57.32

[Conditional expression corresponding value]
Ex1 Ex2 Ex3 Ex4 Ex5 Ex6 Ex7 Ex8 Ex9 Ex10 Ex11
(1) 2.89 2.69 3.17 3.03 3.05 3.41 3.35 3.46 3.40 3.31 2.79
(2) 18.88 18.37 18.96 19.16 18.53 23.94 17.42 23.10 23.57 18.26 18.47
(3) 3.69 3.30 4.17 3.96 3.93 3.96 4.44 4.10 4.43 4.01 3.62
(4) 4.69 4.54 4.98 4.93 4.80 5.06 5.30 5.07 4.55 4.98 4.72
(5) 1.88 1.89 1.86 1.80 1.81 1.84 1.86 1.89 1.82 1.86 1.77
(6) 29.74 29.74 28.43 29.74 35.25 28.43 28.43 29.74 33.27 29.74 32.23
(7) 0.666 0.666 0.669 0.666 0.667 0.669 0.669 0.666 0.668 0.666 0.667
(8) 0.92 0.79 0.73 0.69 0.73 0.75 0.88 0.76 0.79 0.82 0.53
(9) 1.24 1.20 1.25 1.19 1.23 1.16 1.13 1.13 1.18 1.05 1.29
(10) 1.20 1.14 1.30 1.14 1.27 1.36 1.34 1.44 1.27 1.06 1.25
(11) 1.10 0.99 0.99 1.01 1.39 0.95 1.01 0.97 0.95 0.95 1.72

G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group G6 Sixth lens group GR Rear lens group GF Focusing lens group GS Anti-vibration lens group S Aperture stop I Image surface

Claims (8)

The optical system includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a rear lens group GR having a positive refractive power.
The rear lens group GR includes, from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power.
When changing the magnification from the wide-angle end to the telephoto end, the interval between the adjacent lens groups changes, and the third lens group G3 and the fifth lens group G5 move along the same locus,
The first lens group G1 is composed of one negative lens and one positive lens,
the rear lens group GR has a negative lens,
The fourth lens group G4 moves along the optical axis when focusing from an object at infinity to an object at a close distance,
An imaging optical system characterized by satisfying the following conditional expression:
(1) 1.80<f1/fRW<5.50
(2) 12.0<LTW×FnoT/Ymax<30.0
(6) vdRn<50
(7) PgFRn+0.0024×νdRn<0.672
(8) 0.40<|f4|/fT<1.50
however,
f1: focal length of the first lens group G1 fRW: focal length of the rear lens group GR when focusing on infinity at the wide-angle end LTW: total optical length of the imaging optical system at the wide-angle end FnoT: maximum F-number of the imaging optical system at the telephoto end when focusing on infinity Ymax: maximum image height of the imaging optical system νdRn: Abbe number for the d-line of the negative lens located closest to the object among the negative lenses in the rear lens group GR PgFRn: partial dispersion ratio for the g-line and F-line of the negative lens located closest to the object among the negative lenses in the rear lens group GR f4: focal length of the fourth lens group G4 fT: focal length of the imaging optical system at the telephoto end when focusing on infinity The imaging optical system according to claim 1, characterized in that the lens group located closest to the image surface of the rear lens group GR is fixed with respect to the image surface. 3. The imaging optical system according to claim 1, wherein the following condition is satisfied:
(3) 2.00<f1/fW<6.00
however,
f1: focal length of the first lens group G1 fW: focal length of the imaging optical system at the wide-angle end when focused on infinity 4. The imaging optical system according to claim 1, wherein the following condition is satisfied:
(4) 4.00<f1/|f2|<6.50
however,
f1: focal length of the first lens group G1 f2: focal length of the second lens group G2 5. The imaging optical system according to claim 1, wherein the following condition is satisfied:
(5) 1.70<nd1ave
however,
nd1ave: average value of refractive index for d-line of all lenses constituting the first lens group G1 6. An imaging optical system according to claim 1, wherein the following condition is satisfied:
(9) BFT/Ymax<2.00
however,
BFT: Back focus of the imaging optical system at the telephoto end Ymax: Maximum image height of the imaging optical system 7. The imaging optical system according to claim 1, wherein the following condition is satisfied:
(10) 0.80<M1/fW<2.00
however,
M1: Amount of movement of the first lens group G1 during magnification change from the wide-angle end to the telephoto end fW: Focal length of the imaging optical system at the wide-angle end when focusing on infinity 8. The imaging optical system according to claim 1 , wherein the rear lens group GR has a vibration-proof lens group GS which moves including a component in a direction perpendicular to the optical axis, and the following condition is satisfied:
(11) 0.50<|fS|/fW<4.0
however,
fS: focal length of the vibration-proof lens group GS, fW: focal length of the imaging optical system at the wide-angle end when focused on infinity

Images