JP3774938B2 - Camera focus detection device and camera - Google Patents

Description

を算出し、適正蓄積時間の平均値Ｔｍａを求めて次回の蓄積時間に設定する（図４Ｓ７）。
【００６１】
なお、デフォーカス量の検出回数が所定の標本回数（ｈ＋１）に達しないときは（図４Ｓ５）、マイクロプロセッサ２１は、前回までの適正蓄積時間を全て平均化して、次回の蓄積時間とする（図４Ｓ６）。
上述した動作をステップＳ２に戻って繰り返す。
以上説明した動作により、光源のフリッカ現象の影響を簡易な処理で取り除き、蓄積時間のふらつきを確実に防ぐことができる。
【００６２】
そのため、蓄積時間がふらついて、イメージセンサ５９の出力レベルが大きく変動することがなくなり、出力レベルを適正な範囲内に収めることができる。
例えば、フリッカ現象に起因して、被写体光の照度が５０％〜１００％の範囲で正弦波状に周期変動している場合、７０．８％の照度（適正蓄積時間の平均値Ｔｍａの逆数）に応じて、蓄積時間が制御される。
【００６３】
そのため、被写体光の照度が１００％まで上昇しても、
１００／７０．８＝１．４１
により、出力ピーク値Ｐｎは、目標ピーク値Ｐｓの１４１％を超えない。したがって、Ａ／Ｄ変換部２１ａの適正入力レベルの上限値の７０．８％程度に、目標ピーク値Ｐｓを予め定めれば、イメージセンサ５９の出力レベルを、Ａ／Ｄ変換部２１ａの適正入力レベル内に納めることができる。
【００６４】
したがって、イメージセンサ５９の出力が、Ａ／Ｄ変換部２１ａにおいてつぶれるおそれがなくなるので、マイクロプロセッサ２１は、イメージセンサ５９の出力について、焦点検出情報を確実に算出することができる。
次に、別の実施形態について説明する。
図５は、第２の実施形態の動作を示す流れ図である。
【００６５】
なお、第２の実施形態における装置の構成については、第１の実施形態の構成（図２，図３）と同じなので、ここでの説明を省略する。
以下、図２，図３，図５に基づいて、第２の実施形態の動作を説明する。
まず、マイクロプロセッサ２１は、測光部１９から被写体の測光量を取り込み、この測光量に応じて、イメージセンサ５９の蓄積時間を初期設定する。
【００６６】
この状態で、レリーズ釦１１ａが半押しされると、イメージセンサ５９は、光電荷の蓄積を開始する。マイクロプロセッサ２１は、設定された蓄積時間に応じて、光電荷の蓄積を終了させる（図５Ｓ２）。
マイクロプロセッサ２１は、イメージセンサ５９の出力を取り込み、周知の相関演算処理を施してデフォーカス量を算出する（図５Ｓ３）。
【００６７】
次に、マイクロプロセッサ２１は、次回の電荷蓄積時間を次のように決定する。
まず、前回の蓄積時間Ｔｎａと、前回のイメージセンサ５９の出力ピーク値Ｐｎとを用いて、
Ｓｎｂ（ｋ）＝Ｐｎ／Ｔｎａ ・・・（６）
を算出し、前回の照度Ｓｎｂ（ｋ）を求める（図５Ｓ４）。
【００６８】
ここで、デフォーカス量の検出回数が所定の標本回数（ｈ＋１）を超えたときは（図５Ｓ５）、
過去（ｈ＋１）回分の照度Ｓｎｂ（ｋ−ｈ）〜Ｓｎｂ（ｋ）の中から、最大値と最小値とを求め、最大値と最小値との中間値Ｓｍａを算出する（図５Ｓ７）。
この中間値Ｓｍａと、予め定められたイメージセンサ５９の目標ピーク値Ｐｓとを用いて、
Ｔｍａ＝Ｐｓ／Ｓｍａ ・・・（７）
を算出し、次回の蓄積時間Ｔｍａを設定する（図５Ｓ８）。
【００６９】
なお、デフォーカス量の検出回数が所定の標本回数（ｈ＋１）に達しないときは（図５Ｓ５）、マイクロプロセッサ２１は、前回の照度Ｓｎｂ（ｋ）と、予め定められたイメージセンサ５９の目標ピーク値Ｐｓとを用いて、
Ｔｍａ＝Ｐｓ／Ｓｎｂ（ｋ） ・・・（８）
を算出し、次回の蓄積時間Ｔｍａを設定する（図５Ｓ６）。
【００７０】
上述した動作をステップＳ２に戻って繰り返す。
以上説明した動作により、第２の実施形態では、第１の実施形態とほぼ同様の効果を得ることができる。
さらに、第２の実施形態に特有な効果については、複数時点の照度Ｓｎｂ（ｋ）の内で、最小値および最大値のみを処理すればよいので、演算処理に要する記憶量が少なく、かつ中心レベルを簡便かつ迅速に算出することができる点である。
【００７１】
次に、別の実施形態について説明する。
図６は、第３の実施形態の動作を示す流れ図である。
なお、第３の実施形態における装置の構成については、第１の実施形態の構成（図２，図３）と同じなので、ここでの説明を省略する。
【００７２】
以下、図２，図３，図６に基づいて、第３の実施形態の動作を説明する。
まず、マイクロプロセッサ２１は、測光部１９から被写体の測光量を取り込み、この測光量に応じて、イメージセンサ５９の蓄積時間を初期設定する。
この状態で、レリーズ釦１１ａが半押しされると、イメージセンサ５９は、光電荷の蓄積を開始する。マイクロプロセッサ２１は、設定された蓄積時間に応じて、光電荷の蓄積を終了させる（図６Ｓ２）。
【００７３】
マイクロプロセッサ２１は、イメージセンサ５９の出力を取り込み、周知の相関演算処理を施してデフォーカス量を算出する（図６Ｓ３）。
次に、マイクロプロセッサ２１は、次回の電荷蓄積時間を次のように決定する。
まず、前回の蓄積時間Ｔｎａと、前回のイメージセンサ５９の出力ピーク値Ｐｎと、予め定められたイメージセンサ５９の目標ピーク値Ｐｓとを用いて、
Ｔｎｂ（ｋ）＝Ｔｎａ・（Ｐｓ／Ｐｎ） ・・・（４）
を算出し、前回における適正蓄積時間Ｔｎｂ（ｋ）を求める（図６Ｓ４）。
【００７４】
ここで、デフォーカス量の検出回数が所定の標本回数（ｈ＋１）を超えた場合（図６Ｓ５）、マイクロプロセッサ２１は、測光部１９から被写体の測光量を取り込む（図６Ｓ６）。
次に、マイクロプロセッサ２１は、図７に示すように、測光量の上昇に従って、過去の重み比率が高い重み係数Ｗ（ｉ）を選択する（図６Ｓ８）。
【００７５】
ここで、マイクロプロセッサ２１は、過去（ｈ＋１）回分の適正蓄積時間Ｔｎｂ（ｋ−ｈ）〜Ｔｎｂ（ｋ）と、重み係数Ｗ（ｉ）とを用いて、
【数２】

を算出し、次回の蓄積時間Ｔｍａを設定する（図６Ｓ９）。
なお、デフォーカス量の検出回数が所定の標本回数（ｈ＋１）に達しないときは（図６Ｓ５）、マイクロプロセッサ２１は、前回の適正蓄積時間Ｔｎｂ（ｋ）を、次回の蓄積時間Ｔｍａにそのまま設定する（図６Ｓ６）。
【００７６】
上述した動作をステップＳ２に戻って繰り返す。
以上説明した動作により、第３の実施形態では、第１の実施形態とほぼ同様の効果を得ることができる。
さらに、第３の実施形態に特有な効果は、被写体の測光量に応じて、蓄積時間の安定性と応答性との均衡が適宜に変更される点である。
【００７７】
すなわち、暗い被写体のように、蓄積時間が長くてフリッカ現象の目立たない被写体については、過去の重み比率が自動的に小さくなり、蓄積時間の応答性を即座に高めることができる。
一方、明るい被写体のように、蓄積時間が短くてフリッカ現象が顕著に表れる被写体については、過去の重み比率が自動的に高くなり、蓄積時間の安定性を一層高めることができる。
【００７８】
次に、別の実施形態について説明する。
図８は、第４の実施形態の動作を示す流れ図である。
なお、第４の実施形態における装置の構成については、第１の実施形態の構成（図２，図３）と同じなので、ここでの説明を省略する。
【００７９】
以下、図２，図３，図８に基づいて、第４の実施形態の動作を説明する。
まず、マイクロプロセッサ２１は、測光部１９から被写体の測光量を取り込み、この測光量に応じて、イメージセンサ５９の蓄積時間を初期設定する（図８Ｓ１）。
この状態で、レリーズ釦１１ａが半押しされると、イメージセンサ５９は、光電荷の蓄積を開始する。マイクロプロセッサ２１は、設定された蓄積時間に応じて、光電荷の蓄積を終了させる（図８Ｓ２）。
【００８０】
マイクロプロセッサ２１は、イメージセンサ５９の出力を取り込み、周知の相関演算処理を施してデフォーカス量を算出する（図８Ｓ３）。
次に、マイクロプロセッサ２１は、次回の電荷蓄積時間を次のように決定する。
まず、前回の蓄積時間Ｔｎａと、前回のイメージセンサ５９の出力ピーク値Ｐｎと、予め定められたイメージセンサ５９の目標ピーク値Ｐｓとを用いて、
Ｔｎｂ（ｋ）＝Ｔｎａ・（Ｐｓ／Ｐｎ） ・・・（４）
を算出し、前回における適正蓄積時間Ｔｎｂ（ｋ）を求める（図８Ｓ４）。
【００８１】
この状態で、デフォーカス量の検出回数が所定の標本回数（ｈ＋１）を超えた場合（図８Ｓ５）、マイクロプロセッサ２１は、カメラの設定状態が手動焦点調節モードか否かを判定する（図８Ｓ７）。
ここで、手動焦点調節モードの場合、マイクロプロセッサ２１は、過去の重み比率が高い重み係数Ｗ（ｉ）を選択する（図８Ｓ８）。
【００８２】
一方、自動焦点調節モードの場合、マイクロプロセッサ２１は、過去の重み比率が低い重み係数Ｗ（ｉ）を選択する（図８Ｓ９）。
次に、マイクロプロセッサ２１は、過去（ｈ＋１）回分の適正蓄積時間Ｔｎｂ（ｋ−ｈ）〜Ｔｎｂ（ｋ）と、重み係数Ｗ（ｉ）とを用いて、上述の（９）式を算出し、次回の蓄積時間Ｔｍａを設定する（図８Ｓ１０）。
【００８３】
なお、デフォーカス量の検出回数が所定の標本回数（ｈ＋１）に達しないときは（図８Ｓ５）、マイクロプロセッサ２１は、前回の適正蓄積時間Ｔｎｂ（ｋ）を、次回の蓄積時間Ｔｍａに設定する（図８Ｓ６）。
上述した動作をステップＳ２に戻って繰り返す。
以上説明した動作により、第４の実施形態では、第１の実施形態とほぼ同様の効果を得ることができる。
【００８４】
さらに、第４の実施形態に特有な効果は、手動焦点調節モードと自動焦点調節モードとにおいて、蓄積時間の安定性と応答性との均衡が適宜に変更される点である。
すなわち、手動焦点調節モード時には、過去の重み比率が自動的に増加させることにより、焦点検出情報をより確実に検出して表示することができる。
【００８５】
一方、自動焦点調節モード時には、過去の重み比率が自動的に減少するので、カメラアングルの変更や被写体移動などに即座に応じて、蓄積時間を制御することが可能となる。
次に、別の実施形態について説明する。
図９は、第５の実施形態の動作を示す流れ図である。
【００８６】
なお、第５の実施形態における装置の構成については、第１の実施形態の構成（図２，図３）と同じなので、ここでの説明を省略する。
第５の実施形態における動作上の特徴は、カメラの設定状態がシングル焦点調節モードか否かを判定して、適正蓄積時間に乗じる重み係数Ｗ（ｉ）を選択する点である。
【００８７】
すなわち、シングル焦点調節モードの場合、マイクロプロセッサ２１は、過去の重み比率が高い重み係数Ｗ（ｉ）を選択する（図９Ｓ８）。
一方、連続調節モードの場合、マイクロプロセッサ２１は、過去の重み比率が低い重み係数Ｗ（ｉ）を選択する（図９Ｓ９）。
第５の実施形態においても、第１の実施形態とほぼ同様の効果を得ることができる。
【００８８】
さらに、第５の実施形態に特有な効果は、シングル焦点調節モードと連続焦点調節モードとにおいて、蓄積時間の安定性と応答性との均衡が適宜に変更される点である。
すなわち、シングル焦点調節モード時には、過去の重み比率が自動的に増加させることにより、焦点検出情報をより確実に検出して表示することができる。
【００８９】
一方、連続焦点調節モード時には、過去の重み比率が自動的に減少するので、カメラアングルの変更や被写体移動などに即座に応じて、蓄積時間を制御することが可能となる。
次に、別の実施形態について説明する。
図１０は、第６の実施形態の動作を示す流れ図である。
【００９０】
なお、第６の実施形態における装置の構成については、第１の実施形態の構成（図２，図３）と同じなので、ここでの説明を省略する。
第６の実施形態における動作上の特徴は、カメラの設定状態が単写モードか否かを判定して、適正蓄積時間に乗じる重み係数Ｗ（ｉ）を選択する点である。
すなわち、単写モードの場合、マイクロプロセッサ２１は、過去の重み比率が高い重み係数Ｗ（ｉ）を選択する（図１０Ｓ８）。
【００９１】
一方、連写モードの場合、マイクロプロセッサ２１は、過去の重み比率が低い重み係数Ｗ（ｉ）を選択する（図１０Ｓ９）。
第６の実施形態においても、第１の実施形態とほぼ同様の効果を得ることができる。
さらに、第６の実施形態に特有な効果は、単写モードと連写モードとにおいて、蓄積時間の安定性と応答性との均衡が適宜に変更される点である。
【００９２】
すなわち、単写モード時には、過去の重み比率が自動的に増加させることにより、焦点検出情報をより確実に検出して表示することができる。
一方、連写モード時には、過去の重み比率が自動的に減少するので、カメラアングルの変更や被写体移動などに即座に応じて、蓄積時間を制御することが可能となる。
【００９３】
次に、別の実施形態について説明する。
図１１は、第７の実施形態の動作を示す流れ図である。
なお、第７の実施形態における装置の構成については、第１の実施形態の構成（図２，図３）と同じなので、ここでの説明を省略する。
【００９４】
第７の実施形態における動作上の特徴は、被写体の動体判定結果に基づいて、適正蓄積時間に乗じる重み係数Ｗ（ｉ）を選択する点である。
すなわち、静止被写体の場合、マイクロプロセッサ２１は、過去の重み比率が高い重み係数Ｗ（ｉ）を選択する（図１１Ｓ８）。
一方、動体被写体の場合、マイクロプロセッサ２１は、過去の重み比率が低い重み係数Ｗ（ｉ）を選択する（図１１Ｓ９）。
【００９５】
第７の実施形態においても、第１の実施形態とほぼ同様の効果を得ることができる。
さらに、第７の実施形態に特有な効果は、静止被写体と動体被写体とにおいて、蓄積時間の安定性と応答性との均衡が適宜に変更される点である。
【００９６】
すなわち、静止被写体の場合には、過去の重み比率が自動的に増加させることにより、焦点検出情報をより確実に検出して表示することができる。
一方、動体被写体の場合には、過去の重み比率が自動的に減少するので、カメラアングルの変更や被写体移動などに即座に応じて、蓄積時間を制御することが可能となる。
【００９７】
次に、別の実施形態について説明する。
図１２は、第８の実施形態の動作を示す流れ図である。
なお、第８の実施形態における装置の構成については、第１の実施形態の構成（図２，図３）と同じなので、ここでの説明を省略する。
【００９８】
第８の実施形態における動作上の特徴は、撮影光学系１３の焦点距離に応じて、適正蓄積時間に乗じる重み係数Ｗ（ｉ）を選択する点である。
すなわち、焦点距離が短い場合、マイクロプロセッサ２１は、過去の重み比率が高い重み係数Ｗ（ｉ）を選択する（図１２Ｓ８）。
一方、焦点距離が長い場合、マイクロプロセッサ２１は、過去の重み比率が低い重み係数Ｗ（ｉ）を選択する（図１２Ｓ９）。
【００９９】
第８の実施形態においても、第１の実施形態とほぼ同様の効果を得ることができる。
さらに、第８の実施形態に特有な効果は、撮影光学系１３の焦点距離に応じて、蓄積時間の安定性と応答性との均衡が適宜に変更される点である。
すなわち、焦点距離が短い場合には、過去の重み比率が自動的に増加させることにより、焦点検出情報をより確実に検出して表示することができる。
【０１００】
一方、焦点距離が長い場合には、過去の重み比率が自動的に減少するので、頻繁に移動する撮影範囲に即座に応じて、蓄積時間を制御することが可能となる。
なお、上述した実施形態では、「関連量」として、適正蓄積時間もしくは照度を採用しているが、関連量はこれらに限定されるものではなく、光像の照度に換算可能な量であればよい。例えば、適正蓄積時間Ｔｎｂ（ｋ）の逆数値などを関連量としてもよい。
【０１０１】
また、上述した実施形態では、中心レベルとして、平均値もしくは中間値を採用しているが、これに限定されるものではなく、フリッカ現象により変動しない値であればよい。例えば、中央値（メジアン）など算出して中心レベルとしてもよい。
さらに、上述した実施形態では、イメージセンサ５９の出力ピーク値に応じて蓄積時間を制御する焦点検出装置について述べたが、本発明の適用はこれに限定されるものではない。例えば、イメージセンサ５９のフレーム内における平均レベルに応じて蓄積時間を制御する焦点検出装置に本発明を適用してもよい。
【０１０２】
また、上述した実施形態では、位相検出方式の焦点検出装置について述べたが、本発明の適用はこれに限定されるものではない。例えば、焦点検出用光学系１として、所定の基線長だけ離れたレンズを撮影光学系に隣接させて配置することにより、外光パシッブ方式の焦点検出装置に本発明を適用することができる。
さらに、第３の実施形態では、測光部１９の測光量に応じて、重み比率を変更しているが、それに限定されるものではなく、一般的には、測光量に換算可能な量に応じて重み比率を変更すればよい。例えば、イメージセンサ５９の出力レベルや、最新の適正蓄積時間Ｔｎｂ（ｋ）などに応じて、重み比率を変更してもよい。
【０１０３】
【発明の効果】
本発明では、光像の照度、適正となる蓄積時間、または該適正となる蓄積時間の逆数のいずれかを照度に関する量として順次算出し、複数時点の照度に関する量について、平均値、中央値、最大値と最小値との中間値、または重み付け平均値のいずれかを中心レベルとして算出し、その中心レベルから蓄積時間を求めている。
【０１０４】
このような作用により、フリッカ現象の影響を簡易な処理で取り除き、蓄積時間のふらつきを確実に防ぐことができる。
そのため、蓄積時間がふらついて、光電変換手段の出力レベルが大きく変動することがなくなり、出力レベルを適正な範囲内に収めることができる。
また、フリッカ現象の影響で、光電変換手段の出力が白側もしくは黒側につぶれるおそれがなくなるので、一組の光像について位置間隔を正確に算出して、焦点検出情報を確実に検出することができる。
【０１０８】
本発明では、被写体の測光量が上昇するに従って、過去の照度に関する量に乗じる重み比率を増加させる。
したがって、暗い被写体のように、蓄積時間が長くてフリッカ現象の目立たない被写体については、過去の照度に関する量に乗じる重み比率が自動的に小さくなり、蓄積時間の応答性を格段に高めることができる。
【０１０９】
一方、明るい被写体のように、蓄積時間が短くてフリッカ現象が顕著に表れる被写体については、過去の照度に関する量に乗じる重み比率が自動的に高くなり、蓄積時間の安定性を格段に高めることができる。
このように、被写体の測光量に応じて重み比率を変更することにより、撮影状況の変化に適応した「蓄積時間の制御」を実現することができる。
【０１１０】
本発明では、手動焦点調節モード時に、過去の照度に関する量に乗じる重み比率を自動的に増加させる。そのため、蓄積時間の安定性が大幅に高められ、フリッカ現象に起因する光電変換手段の出力つぶれを防止して、焦点検出情報を確実に検出することが可能となる。
したがって、焦点検出情報を継続的に途切れることなく表示でき、手動による焦点調節動作に対して、的確な指針を随時に与えることが可能となる。
【０１１１】
一方、自動焦点調節モード時には、過去の照度に関する量に乗じる重み比率を自動的に減少させる。そのため、フリッカ現象による蓄積時間のふらつきを適度に抑制しつつ、被写体本来の照度変化に対する蓄積時間の応答性を高めることができる。
したがって、（自動焦点調節モード時に頻繁に実行される）カメラアングルの変更や被写体移動などに応じて、蓄積時間を迅速かつ鋭敏に制御することが可能となる。
【０１１２】
このように、手動焦点調節モードと自動焦点調節モードとにおいて重み比率を変更することにより、撮影状況の変化に適応した「蓄積時間の制御」を実現することができる。
本発明では、シングル焦点調節モード時に、過去の照度に関する量に乗じる重み比率を自動的に増加させる。そのため、蓄積時間の安定性が大幅に高められ、フリッカ現象に起因する光電変換手段の出力つぶれを確実に防止して、焦点検出情報を確実に検出することが可能となる。
【０１１３】
したがって、（シングル焦点調節モード時に撮影されることが多い）静止被写体について、焦点検出情報をより確実に検出することが可能となる。
一方、連続焦点調節モード時には、過去の照度に関する量に乗じる重み比率を自動的に減少させる。そのため、フリッカ現象による蓄積時間のふらつきを適度に抑制しつつ、被写体本来の照度変化に対する蓄積時間の応答性を高めることができる。
【０１１４】
したがって、（連続焦点調節モード時に頻繁に実行される）カメラアングルの変更や被写体移動などに応じて、蓄積時間を迅速かつ鋭敏に制御することが可能となる。
このように、シングル焦点調節モードと連続焦点調節モードとにおいて重み比率を変更することにより、撮影状況の変化に適応した「蓄積時間の制御」を実現することができる。
【０１１５】
本発明では、単写モード時に、過去の照度に関する量に乗じる重み比率を自動的に増加させる。そのため、蓄積時間の安定性が大幅に高められ、フリッカ現象に起因する光電変換手段の出力つぶれを確実に防止して、焦点検出情報を確実に検出することが可能となる。
したがって、（単写モード時に撮影されることが多い）静止被写体について、焦点検出情報をより確実に検出することが可能となる。
【０１１６】
一方、連写モード時には、過去の照度に関する量に乗じる重み比率を自動的に減少させる。そのため、フリッカ現象による蓄積時間のふらつきを適度に抑制しつつ、被写体本来の照度変化に対する蓄積時間の応答性を高めることができる。
したがって、（連続撮影の期間中に頻繁に実行される）カメラアングルの変更や被写体移動などに応じて、蓄積時間を迅速かつ鋭敏に制御することが可能となる。
【０１１７】
このように、単写モードと連写モードとにおいて重み比率を変更することにより、撮影状況の変化に適応した「蓄積時間の制御」を実現することができる。
本発明では、静止被写体の場合に、過去の照度に関する量に乗じる重み比率を自動的に増加させる。そのため、蓄積時間の安定性が大幅に高められ、フリッカ現象に起因する光電変換手段の出力つぶれを確実に防止して、焦点検出情報を確実に検出することが可能となる。
【０１１８】
したがって、静止被写体について、焦点検出情報をより確実に検出することが可能となる。
一方、動体被写体の場合には、過去の照度に関する量に乗じる重み比率を自動的に減少させる。そのため、フリッカ現象による蓄積時間のふらつきを適度に抑制しつつ、被写体本来の照度変化に対する蓄積時間の応答性を高めることができる。
【０１１９】
したがって、被写体の動きにより生じる照度変化に応じて、蓄積時間を迅速かつ鋭敏に制御することが可能となる。
このように、静止被写体と動体被写体とにおいて重み比率を変更することにより、撮影状況の変化に適応した「蓄積時間の制御」を実現することができる。
本発明では、撮影光学系の焦点距離が短い場合に、過去の照度に関する量に乗じる重み比率を自動的に増加させる。そのため、蓄積時間の安定性が大幅に高められ、フリッカ現象に起因する光電変換手段の出力つぶれを確実に防止して、焦点検出情報を確実に検出することが可能となる。
【０１２０】
したがって、（撮影画角が広いために照度変化が小さい）被写体について、焦点検出情報をより確実に検出することが可能となる。
一方、撮影光学系の焦点距離が長い場合に、過去の照度に関する量に乗じる重み比率を自動的に減少させる。そのため、フリッカ現象による蓄積時間のふらつきを適度に抑制しつつ、被写体本来の照度変化に対する蓄積時間の応答性を高めることができる。
【０１２１】
したがって、（撮影画角が狭いために頻繁に変化する）被写体の照度変化に応じて、蓄積時間を迅速かつ鋭敏に制御することが可能となる。
このように、撮影光学系の焦点距離に応じて重み比率を変更することにより、撮影状況の変化に適応した「蓄積時間の制御」を実現することができる。
【図面の簡単な説明】
【図１】 本発明の原理ブロック図である。
【図２】 第１の実施形態を示す図である。
【図３】 焦点検出部２０の内部構成を示す分解斜視図である。
【図４】 第１の実施形態の動作を説明する流れ図である。
【図５】 第２の実施形態の動作を示す流れ図である。
【図６】 第３の実施形態の動作を示す流れ図である。
【図７】 重み係数の変更を説明する図である。
【図８】 第４の実施形態の動作を示す流れ図である。
【図９】 第５の実施形態の動作を示す流れ図である。
【図１０】 第６の実施形態の動作を示す流れ図である。
【図１１】 第７の実施形態の動作を示す流れ図である。
【図１２】 第８の実施形態の動作を示す流れ図である。
【図１３】 焦点検出部を示す分解斜視図である。
【図１４】 従来の焦点検出装置の動作を示す流れ図である。
【図１５】 測光量の周期変動を説明する図である。
【符号の説明】
１ 焦点検出用光学系
２ 光電変換手段
３ 照度算出手段
４ 中心算出手段
５ 蓄積時間制御手段
６ 焦点検出手段
１１ カメラボディ
１１ａ レリーズ釦
１２ 鏡筒
１４ メインミラー
１５ サブミラー
１６ マット面
１７ ペンタプリズム
１８ 接眼レンズ
１９ 測光部
２０ 焦点検出部
２１ マイクロプロセッサ
２１ａ Ａ／Ｄ変換部
５０ 焦点検出部
５１ レンズホルダ部
５２ コンデンサレンズ
５３ 視野マスク
５４ 赤外カットフィルタ
５５ ミラー
５７ 絞り板
５７ａ 絞りマスク
５７ｂ 絞りマスク
５８ レンズ板
５８ａ セパレータレンズ
５８ｂ セパレータレンズ
５９ イメージセンサ
６０ マイクロプロセッサ
６０ａ Ａ／Ｄ変換部[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a focus detection apparatus that photoelectrically converts a set of optical images with an image sensor and detects the focus state by detecting the interval between the optical images, and in particular, regardless of the flicker phenomenon of the light source. Focus detection device that adjusts the level within an appropriate rangeAnd cameraAbout.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a focus detection device is mounted on a camera or other optical device in order to detect a distance measurement value of a subject, a defocus amount, or other focus detection information.
FIG. 13 is an exploded perspective view showing this type of focus detection apparatus.
In the figure, a lens holder portion 51 is provided on the upper surface of the focus detection portion 50, and a condenser lens 52 is fitted to the lens holder portion 51.
[0003]
On the upper surface of the condenser lens 52, a field mask 53 for limiting the field of view and an infrared cut filter 54 for blocking infrared light are disposed.
In addition, a mirror 55 is obliquely disposed immediately below the condenser lens 52, and an aperture plate 57, a lens plate 58, and an image sensor 59 are sequentially disposed along the reflection axis of the mirror 55. The output of the image sensor 59 is connected to the microprocessor 60 via the A / D converter 60a.
[0004]
Further, aperture masks 57a and 57b each having a left-right symmetric opening are perforated in the above-described aperture plate 57, and separator lenses 58a and 58b each including a left-right symmetric imaging lens are integrally formed on the lens plate 58. Molded.
FIG. 14 is a flowchart showing the operation of the conventional focus detection apparatus.
[0005]
Hereinafter, the operation of the conventional example will be described with reference to FIGS.
First, the focus detection unit 50 configured as described above is disposed below the mirror box in the camera, and the condenser lens 52 receives the light beam from the photographing optical system.
This light beam reaches the aperture masks 57a and 57b via the mirror 55. In the aperture masks 57a and 57b, an extra light beam is blocked and divided into left and right symmetrical divided light beams. These split light beams are individually tilted through the separator lenses 58 a and 58 b to form a set of light images on the light receiving surface of the image sensor 59.
[0006]
Here, the microprocessor 60 captures the photometric amount of the subject from a photometric unit or the like in the camera. The microprocessor 60 initializes the accumulation time of the image sensor 59 in accordance with the photometric amount (S1 in FIG. 14).
Next, the microprocessor 60 controls the image sensor 59 to execute accumulation of photocharges for the set accumulation time. The photoelectric charges accumulated in this way are sequentially transferred as image signals, A / D converted, and then taken into the microprocessor 60 (S2 in FIG. 14).
[0007]
The microprocessor 60 performs a known correlation operation on the image signal, and detects the position interval of a set of optical images. Based on this position interval, the defocus amount is calculated (S3 in FIG. 14).
Here, the microprocessor 60 uses the peak value Pn of the image signal obtained last time, the previous accumulation time Tn, and the predetermined target peak value Ps,
Tn + 1 = Tn · (Ps / Pn) (1)
Is calculated to obtain the accumulation time Tn + 1 that was appropriate at the previous time (S4 in FIG. 14).
[0008]
The microprocessor 60 sets the appropriate accumulation time Tn + 1 as the next accumulation time (S5 in FIG. 14).
The above operation returns to step S2 and is repeated.
[0009]
By such an operation, the accumulation time of the image sensor 59 follows the appropriate accumulation time Tn + 1 with a delay of one focus detection cycle. Therefore, for an illuminance change that is sufficiently slower than one focus detection cycle, the accumulation time is appropriately controlled, and the output level of the image sensor 59 is always maintained at an appropriate level.
Japanese Patent Application Laid-Open No. 64-79712 discloses an apparatus that intentionally slows down the convergence speed of the accumulation time in an environment where the illuminance of the subject light varies greatly.
[0010]
That is, using the average level Dn in the frame in the image signal obtained last time, the previous accumulation time Tn, and the predetermined target level Ds,
Tn + 1 = (1-W) Tn + W.Tn. (Ds / Dn) (2)
And the next accumulation time Tn + 1 is determined.
In the equation (2), the previous accumulation time Tn and the previous appropriate accumulation time {Tn · (Ds / Dn)} are divided internally by the ratio of the coefficient W to obtain the next accumulation time Tn + 1. It has established.
[0011]
Therefore, the next accumulation time Tn + 1 gradually converges toward the appropriate accumulation time, and a sudden change in the accumulation time is suppressed.
[0012]
[Problems to be solved by the invention]
By the way, when a subject is illuminated using a light source (for example, a fluorescent lamp) in which a flicker phenomenon occurs, the illuminance of the subject light periodically varies as shown in FIG.
[0013]
In the conventional focus detection apparatus, when the illuminance of the subject light varies in this way, the adjustment of the accumulation time cannot be accurately followed, and the output level of the image sensor 59 greatly varies greatly exceeding the illuminance change of the subject light. There was a problem that it would cause (a kind of resonance phenomenon).
For example, in the case shown in FIG. 15, the illuminance of the subject light varies periodically between 50% and 100%. In this case, the peak value Pn of the image signal captured at time T1 is a value of 100%. The microprocessor 60 determines the next accumulation time Tn + 1 corresponding to the 100% peak value Pn based on the equation (1).
[0014]
However, since the illuminance of the subject light is reduced to 50% at the next time T2, the next peak value Pn reaches only half of the target peak value Ps.
Therefore, the microprocessor 60 sets the next accumulation time to the current double.
However, at the next time T3, since the illuminance of the subject light rises again to 100%, the peak value Pn of the image signal reaches twice the target peak value Ps.
[0015]
Thus, the output level fluctuates in the range of 50% to 200% of the target peak value Ps.
Normally, when the output level of the image sensor 59 greatly fluctuates, it exceeds the input range of the A / D converter 60a, and the image signal after A / D conversion is crushed to the white side or the black side. When the image pattern is collapsed in this way, the position interval cannot be accurately detected for a set of light images, and the focus detection accuracy is lowered, or in the worst case, the focus detection is impossible. was there.
[0016]
On the other hand, in the apparatus described in Japanese Patent Application Laid-Open No. 64-79712, fluctuations in the output level due to the flicker phenomenon can be slightly suppressed by uniformly delaying the responsiveness of the accumulation time to the illuminance change. However, since the next accumulation time Tn + 1 is determined only by the previous accumulation time Tn and “previous appropriate accumulation time {Tn · (Ds / Dn)}”, the degree of freedom in design is small, and flicker The fluctuation of the output level due to the phenomenon could not be reduced sufficiently and appropriately.
[0017]
Accordingly, in order to solve the above-described problems, the invention described in claim 1 is a focus detection device that can eliminate the influence of the flicker phenomenon and efficiently suppress the fluctuation of the output level of the image sensor. The purpose is to provide.
[0019]
  ContractClaim2~8In addition to the object of the first aspect, the focus detection apparatus that appropriately changes the balance between the stability of the accumulation time and the responsiveness in a flexible manner in response to a change in the photographing situation and the like.And cameraThe purpose is to provide.
[0020]
[Means for Solving the Problems]
  FIG.Of the present inventionIt is a principle block diagram. Hereinafter, means for solving the problem will be described with reference to FIG.
  According to the first aspect of the present invention, a focus detection optical system 1 that forms a set of light images by dividing and forming light from a subject, and a set of the focus detection optical system 1 formed. The illuminance of the light image based on the photoelectric conversion means 2 for photoelectrically converting the light image, and the output and storage time of the photoelectric conversion means 2Either the appropriate accumulation time or the reciprocal of the appropriate time is the amount related to the illuminance.Illuminance calculation means 3 to calculate, and a plurality of time points sequentially calculated by the illuminance calculation means 3For the illuminance-related quantity, select either the average value, the median value, the intermediate value between the maximum and minimum values, or the weighted average value.Center levelAsIn accordance with the center calculation means 4 to be calculated, the accumulation time control means 5 for controlling the accumulation time of the photoelectric conversion means 2 according to the center level calculated by the center calculation means 4, and the output of the photoelectric conversion means 2 are fetched, and one set And a focus detection means 6 for calculating focus detection information about the subject based on the position interval of the optical image.
[0023]
  Claim2The invention described in claim1In the focus detection apparatus described in (4), the center calculation unit 4 is configured so that the photometric quantity of the subject isincreaseAccording to the pastAbout illuminanceIt is characterized by increasing the weight ratio by which the quantity is multiplied.
  Claim3The invention described in claim1In the focus detection apparatus described in (4), the center calculation means 4 performs the past adjustment at the time of manual focus adjustment.About illuminanceThe weight ratio multiplied by the amount is increased.About illuminanceIt is characterized by reducing the weight ratio by which the quantity is multiplied.
[0024]
  Claim4The invention described in claim1In the focus detection apparatus described in 1), the center calculation means 4 has a single focus adjustment mode.WhenIn the pastAbout illuminanceIncrease the weight ratio multiplied by the amount to adjust the continuous focus adjustment mode.WhenIn the pastAbout illuminanceIt is characterized by reducing the weight ratio by which the quantity is multiplied.
[0025]
  Claim5The invention described in claim1In the focus detection apparatus described in (1), the center calculation unit 4 is configured to store the past in the single shooting mode.About illuminanceIn the continuous shooting mode, the weight ratio multiplied by the amount is increased.About illuminanceIt is characterized by reducing the weight ratio by which the quantity is multiplied.
  Claim6The invention described in claim1In the focus detection apparatus described in (4), the center calculation means 4 is theAbout illuminanceThe weight ratio multiplied by the amount is increased.About illuminanceIt is characterized by reducing the weight ratio by which the quantity is multiplied.
[0026]
  Claim7The invention described in claim1In the focus detection apparatus described in (4), the center calculation means 4 is adapted to reduce the past as the focal length of the photographing optical system becomes shorter.About illuminanceIt is characterized by increasing the weight ratio by which the quantity is multiplied.
  According to an eighth aspect of the present invention, the focus detection apparatus according to any one of the first to seventh aspects is provided.
[0027]
(Function)
In the focus detection apparatus according to the first aspect, a set of optical images is formed via the focus detection optical system 1. These light images are photoelectrically converted via the photoelectric conversion means 2 and output to the illuminance calculation means 3 as image signals.
[0028]
Here, when the output level of the photoelectric conversion means 2 is Pn and the accumulation time is Tn, the illuminance Sn of a set of optical images is
Sn ∝ Pn / Tn (3)
It is represented by Therefore, the illuminance calculation unit 3 calculates a related amount corresponding to the illuminance Sn of the optical image based on the output level Pn of the photoelectric conversion unit 2 and the accumulation time Tn.
[0029]
Next, the center calculation means 4 observes the time variation of the related quantity over a plurality of time points, and calculates the center level. By calculating the center level in this way, it is possible to remove the influence caused by the flicker phenomenon of the light source.
The accumulation time control means 5 controls the accumulation time of the photoelectric conversion means 2 according to the center level.
[0030]
  Therefore, even if a flicker phenomenon occurs, the accumulation time does not resonate, and the output level of the photoelectric conversion means 2 can be kept within an appropriate range..
[0035]
In the focus detection apparatus according to the fifth aspect, the past weight ratio is increased as the photometric amount of the subject increases.
In general, the accumulation time is longer when the photometric amount of the subject is low. In such a case, since the change in illuminance due to the flicker phenomenon is smoothed during the accumulation time, the fluctuation range of the output level in the photoelectric conversion means 2 becomes small.
[0036]
In such a state, the adverse effect of the flicker phenomenon is small conventionally. Therefore, when the photometric quantity of the subject is low, the responsiveness of the accumulation time to the original illuminance change can be improved by reducing the past weight ratio.
On the other hand, when the photometric amount of the subject is high, the accumulation time is shortened. In such a case, the illuminance change due to the flicker phenomenon is not sufficiently smoothed during the accumulation time, and the fluctuation range of the output level in the photoelectric conversion means 2 becomes large.
[0037]
  Therefore, when the photometric quantity of the subject is high, the stability of the accumulation time can be sufficiently improved by increasing the past weight ratio.
  Claim3In the focus detection apparatus according to the above, the above-described weighting factor is changed in the manual focus adjustment mode and the automatic focus adjustment mode.
  In the manual focus adjustment mode, the defocus amount and other focus detection information are displayed on the display unit for the purpose of facilitating manual focus adjustment. In such a display, it is required to indicate the change in focus detection information continuously without interruption.
[0038]
Therefore, it is more important to detect the focus detection information stably and reliably than the output level of the photoelectric conversion means 2 is crushed and focus detection is temporarily impossible.
Further, in the manual focus adjustment mode, there are overwhelmingly many cases where a still subject is photographed carefully, and the original illuminance change is small.
For this reason, in the manual focus adjustment mode, the past weight ratio is increased to further increase the stability of the accumulation time, thereby maximizing the influence of the flicker phenomenon and making the focus detection information stable and stable. Detect reliably.
[0039]
On the other hand, in the automatic focus adjustment mode, the photographer is saved the trouble of focus adjustment, so that there are many cases where the focus adjustment is performed while frequently changing the camera angle. In many cases, the subject is a moving subject that is difficult to adjust manually.
In these cases, since the illuminance change inherent in the subject also becomes severe, responsiveness of the accumulation time is required.
[0040]
For these reasons, in the automatic focus adjustment mode, the responsiveness of the accumulation time is further improved by reducing the past weight ratio.
As described above, “accumulation time control” adapted to changes in photographing conditions can be realized by changing the weighting factor between the manual focus adjustment mode and the automatic focus adjustment mode.
[0041]
  Claim4In the focus detection apparatus related to the above, the above-described weighting factor is changed in the single focus adjustment mode and the continuous focus adjustment mode.
  The single focus adjustment mode is a photographing mode in which focus adjustment is emphasized. Therefore, photographing a still subject carefully is overwhelmingly large, and the original illuminance change is small.
[0042]
For this reason, in the single focus adjustment mode, by increasing the past weight ratio to further increase the stability of the accumulation time, the influence of the flicker phenomenon is eliminated to the maximum, and the focus detection information is stable and stable. Detect reliably.
On the other hand, the continuous focus adjustment mode is a shooting mode in which importance is given to a photo opportunity, and a moving subject is often shot. In such a case, since the illuminance change inherent in the subject becomes intense, the responsiveness of the accumulation time is required.
[0043]
For these reasons, in the continuous focus adjustment mode, the responsiveness of the accumulation time is further enhanced by reducing the past weight ratio.
As described above, “accumulation time control” adapted to changes in the photographing situation can be realized by changing the weighting factor between the single focus adjustment mode and the continuous focus adjustment mode.
[0044]
  Claim5In the focus detection apparatus according to the above, the above-described weighting factor is changed in the single shooting mode and the continuous shooting mode.
  The single-shot mode is overwhelmingly a case where a still subject is photographed carefully, and the illuminance change inherent in the subject is small.
  For these reasons, in single-shot mode, the past weight ratio is increased to further increase the stability of the accumulation time, thereby maximizing the effects of the flicker phenomenon and ensuring stable and reliable focus detection information. To detect.
[0045]
On the other hand, the continuous shooting mode is a shooting mode for surely capturing a suitable photo opportunity, and the moving subject is overwhelmingly photographed. In these cases, the illuminance change inherent in the subject becomes severe, and thus high responsiveness of the accumulation time is required.
Under such circumstances, in the continuous shooting mode, the responsiveness of the accumulation time is further enhanced by reducing the past weight ratio.
[0046]
  As described above, “accumulation time control” adapted to changes in shooting conditions can be realized by changing the weighting factor between the single shooting mode and the continuous shooting mode.
  Claim6In the focus detection apparatus related to the above, the above-described weighting coefficient is changed depending on whether the subject is a stationary body or a moving body.
  In the case of a stationary subject, the original illuminance change does not occur. For this reason, in the case of a stationary subject, the influence of the flicker phenomenon is eliminated to the maximum by increasing the past weight ratio to further increase the stability of the accumulation time, and the focus detection information is stable and reliable. To detect.
[0047]
On the other hand, in the case of a moving subject, the illuminance change inherent in the subject becomes intense, and high responsiveness of the accumulation time is required.
Under such circumstances, the response time of the accumulation time is further enhanced by reducing the past weight ratio when the subject is a moving subject.
[0048]
  As described above, “accumulation time control” adapted to changes in the shooting situation can be realized by changing the weighting coefficient between the stationary subject and the moving subject.
  Claim7In the focus detection apparatus related to the above, the weight ratio is changed according to the focal length of the photographing optical system.
  When the focal length is short, the time change of the defocus amount is small, and the lens extension distance is also short. Accordingly, since it takes a short time to reach the in-focus state, it is desired to stably and reliably detect the focus detection information rather than focusing on the responsiveness of the accumulation time.
[0049]
Further, when the focal length is short, the shooting angle of view becomes wide. For this reason, the displacement of the subject image due to camera shake is small, and the original illuminance change is also small.
For this reason, when the focal length is short, the past weight ratio is increased to further increase the stability of the accumulation time, thereby maximizing the influence of the flicker phenomenon and ensuring stable and reliable focus detection information. To detect.
[0050]
On the other hand, as the focal length becomes longer, the angle of view becomes narrower, so that the displacement of the subject image due to camera shake increases. Therefore, since the illuminance change inherent in the subject becomes intense, high responsiveness of the accumulation time is required.
For these reasons, when the focal length is long, the responsiveness of the accumulation time is further improved by reducing the past weight ratio.
[0051]
  As described above, by changing the weighting coefficient according to the focal length of the photographing optical system, it is possible to realize “accumulation time control” adapted to changes in photographing conditions.
  Since the camera according to the eighth aspect includes the focus detection device according to any one of the first to seventh aspects, the above-described effects of the focus detection device are achieved.
[0052]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0053]
  FIG. 2 shows the first embodiment.TheFIG.
  FIG. 3 is an exploded perspective view showing the internal configuration of the focus detection unit 20.
  In FIG. 2, a lens barrel 12 is attached to the front surface of the camera body 11, and a release button 11 a is disposed on the surface of the camera body 11. An imaging optical system 13 is disposed inside the lens barrel 12.
[0054]
On the optical axis of the photographing optical system 13, a main mirror 14 and a sub mirror 15 are arranged in order, and a mat surface 16 and a pentaprism 17 are arranged along the reflection direction of the main mirror 14.
On the rear surface side of the pentaprism 17, an eyepiece 18 and a photometry unit 19 are disposed, and a focus detection unit 20 is disposed in the reflection direction of the sub mirror 15. The image signal output of the focus detection unit 20 is connected to the microprocessor 21 via the A / D conversion unit 21a.
[0055]
  Control terminals of the release button 11a, the photometry unit 19 and the focus detection unit 20 are connected to the microprocessor 21.
  The internal structure of the focus detection unit 20 shown in FIG. 3 is the same as the structure shown in FIG.
  Also,Block diagram shown in FIG.The focus detection optical system 1 corresponds to the field mask 53, the condenser lens 52, the aperture mask 57a, and the lens plate 58, and the photoelectric conversion unit 2 corresponds to the image sensor 59. The illuminance calculation means 3 corresponds to the “appropriate accumulation time calculation function” in the microprocessor 21, the center calculation means 4 corresponds to the “center level calculation function” in the microprocessor 21, and the accumulation time control means 5 corresponds to the microprocessor 21. The focus detection means 6 corresponds to the “defocus amount calculation function” in the microprocessor 21, and the “related amount” corresponds to “appropriate storage time”.
[0056]
FIG. 4 is a flowchart for explaining the operation of the present embodiment.
Hereinafter, the operation of the present embodiment will be described with reference to FIGS.
First, when the mirror is down, subject light is reflected through the main mirror 14 and a subject image is formed on the mat surface 16. The subject image is scattered through the mat surface 16 and then observed from the outside through the pentaprism 17 and the eyepiece 18.
[0057]
A part of the light scattered by the mat surface 16 is measured by the photometry unit 19.
On the other hand, the light beam that has passed through the light transmission part of the main mirror 14 is reflected by the sub mirror 15 and irradiated onto the focus detection part 20.
First, the microprocessor 21 initially sets the accumulation time based on the photometric amount of the photometric unit 19 (S1 in FIG. 4).
[0058]
In this state, the image sensor 59 starts accumulating photoelectric charges. The microprocessor 21 ends the accumulation of photocharges according to the set accumulation time (S2 in FIG. 4).
The microprocessor 21 takes in the output of the image sensor 59 and performs a known correlation calculation process to calculate a defocus amount (S3 in FIG. 4).
[0059]
Next, the microprocessor 21 determines the next charge accumulation time as follows.
First, using the previous accumulation time Tna, the output peak value Pn of the previous image sensor 59, and the target peak value Ps determined from the appropriate input level of the A / D converter 21a,
Tnb (k) = Tna · (Ps / Pn) (4)
Is calculated, and the previous appropriate accumulation time Tnb (k) is obtained (S4 in FIG. 4).
[0060]
Here, when the number of detections of the defocus amount exceeds a predetermined number of samples (h + 1) (S5 in FIG. 4),
Using the appropriate accumulation times Tnb (k−h) to Tnb (k) for the past (h + 1) times,
[Expression 1]

Is calculated, and an average value Tma of appropriate accumulation times is obtained and set to the next accumulation time (S7 in FIG. 4).
[0061]
When the number of detections of the defocus amount does not reach the predetermined number of samples (h + 1) (S5 in FIG. 4), the microprocessor 21 averages all the appropriate accumulation times up to the previous time to obtain the next accumulation time ( FIG. 4S6).
The above operation returns to step S2 and is repeated.
By the operation described above, the influence of the flicker phenomenon of the light source can be removed by a simple process, and the fluctuation of the accumulation time can be surely prevented.
[0062]
Therefore, the accumulation time fluctuates and the output level of the image sensor 59 does not fluctuate greatly, and the output level can be kept within an appropriate range.
For example, when the illuminance of the subject light periodically varies sinusoidally in the range of 50% to 100% due to the flicker phenomenon, the illuminance is 70.8% (the reciprocal of the average value Tma of the appropriate accumulation time). Accordingly, the accumulation time is controlled.
[0063]
Therefore, even if the illuminance of subject light increases to 100%,
100 / 70.8 = 1.41
Therefore, the output peak value Pn does not exceed 141% of the target peak value Ps. Therefore, if the target peak value Ps is determined in advance to about 70.8% of the upper limit value of the appropriate input level of the A / D converter 21a, the output level of the image sensor 59 is changed to the appropriate input of the A / D converter 21a. Can be within the level.
[0064]
  Therefore, there is no possibility that the output of the image sensor 59 is crushed in the A / D conversion unit 21a, so that the microprocessor 21 can reliably calculate the focus detection information for the output of the image sensor 59.
  Next, another embodiment will be described.
  FIG. 5 shows the second embodiment.ofIt is a flowchart which shows operation | movement.
[0065]
Note that the configuration of the apparatus in the second embodiment is the same as the configuration of the first embodiment (FIGS. 2 and 3), and a description thereof will be omitted here.
The operation of the second embodiment will be described below with reference to FIGS.
First, the microprocessor 21 takes in the photometric amount of the subject from the photometric unit 19 and initializes the accumulation time of the image sensor 59 according to the photometric amount.
[0066]
In this state, when the release button 11a is half-pressed, the image sensor 59 starts accumulating photoelectric charges. The microprocessor 21 ends the accumulation of photocharges according to the set accumulation time (S2 in FIG. 5).
The microprocessor 21 takes in the output of the image sensor 59, performs a known correlation calculation process, and calculates the defocus amount (S3 in FIG. 5).
[0067]
Next, the microprocessor 21 determines the next charge accumulation time as follows.
First, using the previous accumulation time Tna and the output peak value Pn of the previous image sensor 59,
Snb (k) = Pn / Tna (6)
And the previous illuminance Snb (k) is obtained (S4 in FIG. 5).
[0068]
Here, when the number of detections of the defocus amount exceeds the predetermined number of samples (h + 1) (S5 in FIG. 5),
The maximum value and the minimum value are obtained from the past (h + 1) illuminances Snb (kh) to Snb (k), and an intermediate value Sma between the maximum value and the minimum value is calculated (S7 in FIG. 5).
Using the intermediate value Sma and a predetermined target peak value Ps of the image sensor 59,
Tma = Ps / Sma (7)
And the next accumulation time Tma is set (S8 in FIG. 5).
[0069]
When the number of detections of the defocus amount does not reach the predetermined number of samples (h + 1) (S5 in FIG. 5), the microprocessor 21 determines the previous illuminance Snb (k) and a predetermined target peak of the image sensor 59. Using the value Ps,
Tma = Ps / Snb (k) (8)
And the next accumulation time Tma is set (S6 in FIG. 5).
[0070]
The above operation returns to step S2 and is repeated.
By the operation described above, the second embodiment can obtain substantially the same effect as the first embodiment.
Furthermore, as for the effects peculiar to the second embodiment, only the minimum value and the maximum value among the illuminance Snb (k) at a plurality of points in time need to be processed. The level can be calculated easily and quickly.
[0071]
  Next, another embodiment will be described.
  FIG. 6 shows a third embodiment.ofIt is a flowchart which shows operation | movement.
  Note that the configuration of the apparatus in the third embodiment is the same as the configuration of the first embodiment (FIGS. 2 and 3), and a description thereof will be omitted here.
[0072]
Hereinafter, the operation of the third embodiment will be described with reference to FIGS.
First, the microprocessor 21 takes in the photometric amount of the subject from the photometric unit 19 and initializes the accumulation time of the image sensor 59 according to the photometric amount.
In this state, when the release button 11a is half-pressed, the image sensor 59 starts accumulating photoelectric charges. The microprocessor 21 ends the accumulation of photocharges according to the set accumulation time (S2 in FIG. 6).
[0073]
The microprocessor 21 takes in the output of the image sensor 59 and performs a known correlation calculation process to calculate the defocus amount (S3 in FIG. 6).
Next, the microprocessor 21 determines the next charge accumulation time as follows.
First, using the previous accumulation time Tna, the previous output peak value Pn of the image sensor 59, and the predetermined target peak value Ps of the image sensor 59,
Tnb (k) = Tna · (Ps / Pn) (4)
Is calculated, and the previous appropriate accumulation time Tnb (k) is obtained (S4 in FIG. 6).
[0074]
Here, when the number of detections of the defocus amount exceeds the predetermined number of samples (h + 1) (S5 in FIG. 6), the microprocessor 21 captures the photometric amount of the subject from the photometry unit 19 (S6 in FIG. 6).
Next, as shown in FIG. 7, the microprocessor 21 selects a weighting factor W (i) having a high past weight ratio as the photometric quantity increases (S8 in FIG. 6).
[0075]
Here, the microprocessor 21 uses the past (h + 1) appropriate accumulation times Tnb (k−h) to Tnb (k) and the weighting coefficient W (i),
[Expression 2]

And the next accumulation time Tma is set (S9 in FIG. 6).
When the number of detections of the defocus amount does not reach the predetermined number of samples (h + 1) (S5 in FIG. 6), the microprocessor 21 sets the previous appropriate accumulation time Tnb (k) as the next accumulation time Tma as it is. (S6 in FIG. 6).
[0076]
The above operation returns to step S2 and is repeated.
By the operation described above, the third embodiment can obtain substantially the same effect as the first embodiment.
Furthermore, an effect peculiar to the third embodiment is that the balance between the stability of the accumulation time and the responsiveness is appropriately changed according to the photometric amount of the subject.
[0077]
That is, for a subject that has a long accumulation time and does not show a flicker phenomenon, such as a dark subject, the past weight ratio automatically decreases, and the responsiveness of the accumulation time can be immediately improved.
On the other hand, for a subject that has a short accumulation time and has a noticeable flicker phenomenon, such as a bright subject, the past weight ratio automatically increases, and the stability of the accumulation time can be further enhanced.
[0078]
  Next, another embodiment will be described.
  FIG. 8 shows a fourth embodiment.ofIt is a flowchart which shows operation | movement.
  Note that the configuration of the apparatus in the fourth embodiment is the same as the configuration of the first embodiment (FIGS. 2 and 3), and a description thereof will be omitted here.
[0079]
The operation of the fourth embodiment will be described below with reference to FIGS.
First, the microprocessor 21 takes in the photometric amount of the subject from the photometric unit 19, and initializes the accumulation time of the image sensor 59 in accordance with the photometric amount (S1 in FIG. 8).
In this state, when the release button 11a is half-pressed, the image sensor 59 starts accumulating photoelectric charges. The microprocessor 21 ends the accumulation of photocharges according to the set accumulation time (S2 in FIG. 8).
[0080]
The microprocessor 21 takes in the output of the image sensor 59 and performs a known correlation calculation process to calculate the defocus amount (S3 in FIG. 8).
Next, the microprocessor 21 determines the next charge accumulation time as follows.
First, using the previous accumulation time Tna, the previous output peak value Pn of the image sensor 59, and the predetermined target peak value Ps of the image sensor 59,
Tnb (k) = Tna · (Ps / Pn) (4)
Is calculated and the previous appropriate accumulation time Tnb (k) is obtained (S4 in FIG. 8).
[0081]
In this state, when the number of detections of the defocus amount exceeds the predetermined number of samples (h + 1) (FIG. 8 S5), the microprocessor 21 determines whether or not the camera setting state is the manual focus adjustment mode (S7 in FIG. 8). ).
Here, in the manual focus adjustment mode, the microprocessor 21 selects a weight coefficient W (i) having a high past weight ratio (S8 in FIG. 8).
[0082]
On the other hand, in the automatic focus adjustment mode, the microprocessor 21 selects a weight coefficient W (i) having a low past weight ratio (S9 in FIG. 8).
Next, the microprocessor 21 calculates the above equation (9) using the past (h + 1) times of appropriate accumulation times Tnb (k−h) to Tnb (k) and the weighting factor W (i). Then, the next accumulation time Tma is set (S10 in FIG. 8).
[0083]
When the number of detections of the defocus amount does not reach the predetermined number of samples (h + 1) (S5 in FIG. 8), the microprocessor 21 sets the previous appropriate accumulation time Tnb (k) as the next accumulation time Tma. (FIG. 8 S6).
The above operation returns to step S2 and is repeated.
By the operation described above, the fourth embodiment can obtain substantially the same effect as the first embodiment.
[0084]
Furthermore, an effect peculiar to the fourth embodiment is that the balance between the stability of the accumulation time and the responsiveness is appropriately changed in the manual focus adjustment mode and the automatic focus adjustment mode.
That is, in the manual focus adjustment mode, the past weight ratio is automatically increased, so that the focus detection information can be detected and displayed more reliably.
[0085]
  On the other hand, in the automatic focus adjustment mode, since the past weight ratio automatically decreases, the accumulation time can be controlled immediately in response to a change in the camera angle or movement of the subject.
  Next, another embodiment will be described.
  FIG. 9 shows a fifth embodiment.ofIt is a flowchart which shows operation | movement.
[0086]
Note that the configuration of the apparatus in the fifth embodiment is the same as the configuration of the first embodiment (FIGS. 2 and 3), and a description thereof will be omitted here.
The operational feature in the fifth embodiment is that it is determined whether or not the camera setting state is the single focus adjustment mode, and a weighting factor W (i) to be multiplied by the appropriate accumulation time is selected.
[0087]
That is, in the single focus adjustment mode, the microprocessor 21 selects a weighting factor W (i) having a high past weight ratio (S8 in FIG. 9).
On the other hand, in the continuous adjustment mode, the microprocessor 21 selects a weight coefficient W (i) having a low past weight ratio (S9 in FIG. 9).
Also in the fifth embodiment, substantially the same effect as in the first embodiment can be obtained.
[0088]
Furthermore, the effect peculiar to the fifth embodiment is that the balance between the stability of the accumulation time and the responsiveness is appropriately changed between the single focus adjustment mode and the continuous focus adjustment mode.
That is, in the single focus adjustment mode, the focus detection information can be detected and displayed more reliably by automatically increasing the past weight ratio.
[0089]
  On the other hand, in the continuous focus adjustment mode, since the past weight ratio automatically decreases, the accumulation time can be controlled immediately in response to a change in the camera angle or movement of the subject.
  Next, another embodiment will be described.
  FIG. 10 shows a sixth embodiment.ofIt is a flowchart which shows operation | movement.
[0090]
Note that the configuration of the apparatus in the sixth embodiment is the same as the configuration of the first embodiment (FIGS. 2 and 3), and a description thereof will be omitted here.
An operational feature of the sixth embodiment is that it is determined whether or not the camera setting state is the single shooting mode, and a weighting factor W (i) to be multiplied by an appropriate accumulation time is selected.
That is, in the single shooting mode, the microprocessor 21 selects a weighting factor W (i) having a high past weight ratio (S8 in FIG. 10).
[0091]
On the other hand, in the continuous shooting mode, the microprocessor 21 selects a weight coefficient W (i) having a low past weight ratio (S9 in FIG. 10).
Also in the sixth embodiment, substantially the same effect as in the first embodiment can be obtained.
Furthermore, an effect peculiar to the sixth embodiment is that the balance between the stability of the accumulation time and the responsiveness is appropriately changed between the single shooting mode and the continuous shooting mode.
[0092]
In other words, in the single shooting mode, the focus detection information can be detected and displayed more reliably by automatically increasing the past weight ratio.
On the other hand, in the continuous shooting mode, since the past weight ratio automatically decreases, the accumulation time can be controlled immediately in response to a change in the camera angle or movement of the subject.
[0093]
  Next, another embodiment will be described.
  FIG. 11 shows the seventh embodiment.ofIt is a flowchart which shows operation | movement.
  Note that the configuration of the apparatus in the seventh embodiment is the same as the configuration of the first embodiment (FIGS. 2 and 3), and a description thereof will be omitted here.
[0094]
An operational feature of the seventh embodiment is that a weighting factor W (i) to be multiplied by the appropriate accumulation time is selected based on the moving object determination result of the subject.
That is, in the case of a stationary subject, the microprocessor 21 selects a weighting factor W (i) having a high past weight ratio (S8 in FIG. 11).
On the other hand, in the case of a moving subject, the microprocessor 21 selects a weight coefficient W (i) having a low past weight ratio (S9 in FIG. 11).
[0095]
Also in the seventh embodiment, substantially the same effect as in the first embodiment can be obtained.
Furthermore, an effect peculiar to the seventh embodiment is that the balance between the stability of the accumulation time and the responsiveness is appropriately changed between the stationary subject and the moving subject.
[0096]
That is, in the case of a stationary subject, the focus detection information can be detected and displayed more reliably by automatically increasing the past weight ratio.
On the other hand, in the case of a moving subject, the past weight ratio automatically decreases, so that the accumulation time can be controlled immediately in response to a change in the camera angle or movement of the subject.
[0097]
  Next, another embodiment will be described.
  FIG. 12 shows an eighth embodiment.ofIt is a flowchart which shows operation | movement.
  Note that the configuration of the apparatus in the eighth embodiment is the same as the configuration of the first embodiment (FIGS. 2 and 3), and a description thereof will be omitted here.
[0098]
An operational feature of the eighth embodiment is that a weighting factor W (i) to be multiplied by an appropriate accumulation time is selected according to the focal length of the photographing optical system 13.
That is, when the focal length is short, the microprocessor 21 selects a weight coefficient W (i) having a high past weight ratio (S8 in FIG. 12).
On the other hand, when the focal length is long, the microprocessor 21 selects a weight coefficient W (i) having a low past weight ratio (S9 in FIG. 12).
[0099]
In the eighth embodiment, substantially the same effect as that of the first embodiment can be obtained.
Furthermore, an effect peculiar to the eighth embodiment is that the balance between the stability of the accumulation time and the responsiveness is appropriately changed according to the focal length of the photographing optical system 13.
That is, when the focal length is short, the past weight ratio is automatically increased, so that the focus detection information can be detected and displayed more reliably.
[0100]
On the other hand, when the focal length is long, the past weight ratio automatically decreases, so that the accumulation time can be controlled immediately according to the frequently moving shooting range.
In the above-described embodiment, an appropriate accumulation time or illuminance is adopted as the “related amount”, but the related amount is not limited to these, and any amount that can be converted into the illuminance of the light image. Good. For example, an inverse value of the appropriate accumulation time Tnb (k) may be used as the related amount.
[0101]
In the above-described embodiment, the average value or the intermediate value is adopted as the center level. However, the present invention is not limited to this, and any value that does not vary due to the flicker phenomenon may be used. For example, the median (median) or the like may be calculated to obtain the center level.
Furthermore, in the above-described embodiment, the focus detection device that controls the accumulation time according to the output peak value of the image sensor 59 has been described, but the application of the present invention is not limited to this. For example, the present invention may be applied to a focus detection apparatus that controls the accumulation time according to the average level in the frame of the image sensor 59.
[0102]
In the above-described embodiment, the phase detection type focus detection apparatus has been described. However, the application of the present invention is not limited to this. For example, as the focus detection optical system 1, the present invention can be applied to an external light passive focus detection device by disposing a lens separated by a predetermined baseline length adjacent to a photographing optical system.
Furthermore, in the third embodiment, the weight ratio is changed according to the photometric amount of the photometric unit 19, but the present invention is not limited to this, and in general, according to the amount that can be converted into the photometric amount. The weight ratio may be changed. For example, the weight ratio may be changed according to the output level of the image sensor 59, the latest appropriate accumulation time Tnb (k), or the like.
[0103]
【The invention's effect】
  BookIn the invention,Either the illuminance of the light image, the appropriate accumulation time, or the reciprocal of the appropriate accumulation time is sequentially calculated as an illuminance quantity, and the average, median, maximum and minimum values for the illuminance quantities at multiple time points are calculated. Calculate either the middle value of the value or the weighted average value as the center level,The accumulation time is calculated from the central level.
[0104]
By such an operation, the influence of the flicker phenomenon can be removed by a simple process, and the fluctuation of the accumulation time can be surely prevented.
Therefore, the accumulation time fluctuates and the output level of the photoelectric conversion means does not fluctuate greatly, and the output level can be kept within an appropriate range.
In addition, since there is no possibility of the output of the photoelectric conversion means being crushed to the white side or the black side due to the flicker phenomenon, the position interval for a set of light images can be accurately calculated to reliably detect the focus detection information. Can do.
[0108]
  BookIn the invention, as the photometric amount of the subject increases, the pastMultiply the amount related to illuminanceIncrease the weight ratio.
  Therefore, for subjects that have a long accumulation time and are not prone to flicker, such as dark subjects,Multiply the amount related to illuminanceThe weight ratio is automatically reduced, and the responsiveness of the accumulation time can be greatly improved.
[0109]
  On the other hand, for subjects that have a short accumulation time and a noticeable flicker phenomenon, such as bright subjects,Multiply the amount related to illuminanceThe weight ratio is automatically increased, and the stability of the accumulation time can be greatly improved.
  As described above, by changing the weight ratio according to the photometric amount of the subject, it is possible to realize “accumulation time control” adapted to the change in the photographing situation.
[0110]
  BookIn the invention, in the manual focus adjustment mode, the pastMultiply the amount related to illuminanceAutomatically increase the weight ratio. Therefore, the stability of the accumulation time is greatly improved, and the output detection of the photoelectric conversion means due to the flicker phenomenon can be prevented, and the focus detection information can be reliably detected.
  Therefore, the focus detection information can be continuously displayed without interruption, and an accurate guideline can be given at any time for manual focus adjustment operation.
[0111]
  On the other hand, in the auto focus mode,Multiply the amount related to illuminanceAutomatically reduce the weight ratio. Therefore, it is possible to enhance the responsiveness of the accumulation time with respect to the original illuminance change while appropriately suppressing the fluctuation of the accumulation time due to the flicker phenomenon.
  Therefore, it is possible to control the accumulation time quickly and sharply in accordance with a change in camera angle or movement of a subject (which is frequently executed in the automatic focus adjustment mode).
[0112]
  As described above, by changing the weight ratio between the manual focus adjustment mode and the automatic focus adjustment mode, it is possible to realize “accumulation time control” adapted to the change in the photographing situation.
  BookIn the invention, in the single focus adjustment mode, the pastMultiply the amount related to illuminanceAutomatically increase the weight ratio. For this reason, the stability of the accumulation time is greatly enhanced, and the output conversion of the photoelectric conversion means due to the flicker phenomenon is surely prevented, and the focus detection information can be reliably detected.
[0113]
  Therefore, it is possible to more reliably detect focus detection information for a stationary subject (which is often photographed in the single focus adjustment mode).
  On the other hand, in the continuous focus adjustment mode,Multiply the amount related to illuminanceAutomatically reduce the weight ratio. Therefore, it is possible to enhance the responsiveness of the accumulation time with respect to the original illuminance change while appropriately suppressing the fluctuation of the accumulation time due to the flicker phenomenon.
[0114]
Therefore, it is possible to control the accumulation time quickly and sharply in accordance with a change in camera angle or movement of a subject (which is frequently executed in the continuous focus adjustment mode).
As described above, by changing the weight ratio between the single focus adjustment mode and the continuous focus adjustment mode, it is possible to realize “accumulation time control” adapted to a change in the photographing situation.
[0115]
  BookIn the invention, in single shooting mode,Multiply the amount related to illuminanceAutomatically increase the weight ratio. For this reason, the stability of the accumulation time is greatly enhanced, and the output conversion of the photoelectric conversion means due to the flicker phenomenon is surely prevented, and the focus detection information can be reliably detected.
  Therefore, it is possible to more reliably detect the focus detection information for a stationary subject (often taken in the single shooting mode).
[0116]
  On the other hand, in continuous shooting mode,Multiply the amount related to illuminanceAutomatically reduce the weight ratio. Therefore, it is possible to enhance the responsiveness of the accumulation time with respect to the original illuminance change while appropriately suppressing the fluctuation of the accumulation time due to the flicker phenomenon.
  Therefore, the accumulation time can be quickly and sharply controlled in accordance with a change in camera angle or movement of a subject (which is frequently executed during a continuous shooting period).
[0117]
  As described above, by changing the weight ratio between the single shooting mode and the continuous shooting mode, it is possible to realize “accumulation time control” adapted to the change of the shooting situation.
  BookIn the invention, in the case of a stationary subject, the pastMultiply the amount related to illuminanceAutomatically increase the weight ratio. For this reason, the stability of the accumulation time is greatly enhanced, and the output conversion of the photoelectric conversion means due to the flicker phenomenon is surely prevented, and the focus detection information can be reliably detected.
[0118]
  Therefore, focus detection information can be detected more reliably for a stationary subject.
  On the other hand, in the case of a moving subject,Multiply the amount related to illuminanceAutomatically reduce the weight ratio. Therefore, it is possible to enhance the responsiveness of the accumulation time with respect to the original illuminance change while appropriately suppressing the fluctuation of the accumulation time due to the flicker phenomenon.
[0119]
  Therefore, it is possible to quickly and sharply control the accumulation time according to the illuminance change caused by the movement of the subject.
  As described above, by changing the weight ratio between the stationary subject and the moving subject, it is possible to realize “accumulation time control” adapted to the change in the photographing situation.
  BookIn the invention, when the focal length of the photographing optical system is short, the pastMultiply the amount related to illuminanceAutomatically increase the weight ratio. For this reason, the stability of the accumulation time is greatly enhanced, and the output conversion of the photoelectric conversion means due to the flicker phenomenon is surely prevented, and the focus detection information can be reliably detected.
[0120]
  Therefore, it is possible to detect the focus detection information more reliably for the subject (the change in illuminance is small because the shooting angle of view is wide).
  On the other hand, when the focal length of the photographic optical system is long,Multiply the amount related to illuminanceAutomatically reduce the weight ratio. Therefore, it is possible to enhance the responsiveness of the accumulation time with respect to the original illuminance change while appropriately suppressing the fluctuation of the accumulation time due to the flicker phenomenon.
[0121]
Therefore, the accumulation time can be quickly and sharply controlled according to the change in the illuminance of the subject (which changes frequently due to the narrow angle of view).
As described above, by changing the weight ratio according to the focal length of the photographing optical system, it is possible to realize “accumulation time control” adapted to changes in photographing conditions.
[Brief description of the drawings]
[Figure 1]Of the present inventionIt is a principle block diagram.
FIG. 2 is a first embodiment.TheFIG.
FIG. 3 is an exploded perspective view showing an internal configuration of the focus detection unit 20;
FIG. 4 is a flowchart illustrating the operation of the first embodiment.
FIG. 5 is a second embodiment.ofIt is a flowchart which shows operation | movement.
FIG. 6 is a third embodiment.ofIt is a flowchart which shows operation | movement.
FIG. 7 is a diagram illustrating a change of a weighting factor.
FIG. 8 is a fourth embodiment.ofIt is a flowchart which shows operation | movement.
FIG. 9 is a fifth embodiment.ofIt is a flowchart which shows operation | movement.
FIG. 10 shows a sixth embodiment.ofIt is a flowchart which shows operation | movement.
FIG. 11 shows a seventh embodiment.ofIt is a flowchart which shows operation | movement.
FIG. 12 is an eighth embodiment.ofIt is a flowchart which shows operation | movement.
FIG. 13 is an exploded perspective view showing a focus detection unit.
FIG. 14 is a flowchart showing the operation of a conventional focus detection apparatus.
FIG. 15 is a diagram for explaining a periodic variation in photometry.
[Explanation of symbols]
  1 Optical system for focus detection
  2 photoelectric conversion means
  3 Illuminance calculation means
  4 Center calculation means
  5 Accumulation time control means
  6 Focus detection means
  11 Camera body
  11a Release button
  12 Lens tube
  14 Main mirror
  15 Submirror
  16 Matt surface
  17 Penta prism
  18 Eyepiece
  19 Metering unit
  20 Focus detector
  21 Microprocessor
  21a A / D converter
  50 Focus detector
  51 Lens holder
  52 condenser lens
  53 Field mask
  54 Infrared cut filter
  55 Mirror
  57 Aperture plate
  57a Aperture mask
  57b Aperture mask
  58 Lens plate
  58a Separator lens
  58b Separator lens
  59 Image sensor
  60 microprocessor
  60a A / D converter

Claims (8)

A focus detection optical system that divides the light from the subject and forms the images separately to form a set of light images;
Photoelectric conversion means for photoelectrically converting the set of optical images formed via the focus detection optical system;
Illuminance calculation means for calculating, as an amount related to the illuminance , an illuminance of the optical image, an appropriate accumulation time, or a reciprocal of the appropriate accumulation time based on the output and the accumulation time of the photoelectric conversion means; ,
Center calculation means for calculating, as a central level , an average value, a median value, an intermediate value between a maximum value and a minimum value, or a weighted average value for an amount related to the illuminance at a plurality of time points sequentially calculated by the illuminance calculation means. When,
Accumulation time control means for controlling the accumulation time of the photoelectric conversion means according to the center level calculated by the center calculation means;
A focus detection apparatus comprising: focus detection means that takes in an output of the photoelectric conversion means and calculates focus detection information about the subject based on a position interval of the set of optical images. The focus detection apparatus according to claim 1 ,
The center calculating means includes
Accordance metering amount of the object is increased, the focus detection apparatus characterized by increasing the weight ratio to be multiplied by the amount of past said illuminance. The focus detection apparatus according to claim 1 ,
The center calculating means includes
A focus detection apparatus that increases a weight ratio by which the amount related to the past illuminance is multiplied during manual focus adjustment, and decreases a weight ratio that is multiplied by the amount related to the past illuminance during automatic focus adjustment. The focus detection apparatus according to claim 1 ,
The center calculating means includes
During single focusing mode, increasing the weight ratio to be multiplied by the amount of past the illuminance at the time of continuous focusing mode, and wherein the reducing the weight ratio to be multiplied by the amount of past said illumination Focus detection device. The focus detection apparatus according to claim 1 ,
The center calculating means includes
A focus detection apparatus that increases a weight ratio by which the amount related to the past illuminance is multiplied in the single shooting mode, and decreases a weight ratio to be multiplied by the amount related to the past illuminance in the continuous shooting mode. The focus detection apparatus according to claim 1 ,
The center calculating means includes
For still subject increases the weight ratio to be multiplied by the amount of past the illuminance, for body subject, focus detection device, characterized in that to reduce the weight ratio to be multiplied by the amount of past said illuminance. The focus detection apparatus according to claim 1 ,
The center calculating means includes
A focus detection apparatus that increases a weight ratio by which the amount related to the past illuminance is multiplied as the focal length of the photographing optical system becomes shorter. A camera comprising the focus detection device according to any one of claims 1 to 7.

Images