| 摘要 |
PURPOSE:To reduce a photometric error easily by providing an exposure correcting member which corrects an exposure aperture diameter by zooming and a photometric correcting member which corrects a photometric aperture diameter by zooming, and by correcting a difference between the exposure and photometric aperture diameters according to zooming. CONSTITUTION:On taking a picture, aperture blades 5 are held open and an aperture diameter in this state is determined on the basis of a position where the pin 15 of a toothed lock washer 3 moving in an optical axis direction corresponding variations in focal length by zooming comes into contact with the cam surface 17 of an open-aperture correcting cam member 16. Once a shutter is released, the release mechanism of a camera body side moves an automatic aperture lever 11 to the right in the figure, an automatic aperture ring 1 turns counterclockwise through the operation of a spring 9, and the toothed lock washer 3 also turns counterclockwise by a spring 13 through a pin 12 to turn a crank member 20 clockwise around a shaft 19 through the turning of the washer until a crank pin 22 meets the cam part 23 of an aperture cam ring 2, thereby stopping down a lens to an aperture diameter which corresponds to the turning position of this aperture ring 2. |
