Patent ID: 7942592

Claim:
A camera diaphragm device comprising: a base plate having an aperture portion in which an optical axis serves as center; an auxiliary plate having an aperture portion in which an optical axis serves as center, a blade chamber being formed between the auxiliary plate and the base plate, either the aperture portion of the auxiliary plate or the aperture portion of the base plate serving as an exposure aperture portion that restricts a maximum diaphragm aperture; a first diaphragm blade having a diaphragm aperture portion which restricts a minimum diaphragm aperture, the first diaphragm blade being mounted to the base plate so that, by a driving pin of first driving means, the first diaphragm blade is reciprocatingly rotated to move to and away from the exposure aperture portion, the first diaphragm blade having a shape that causes an incapable-of-covering area to exist in addition to an area of the diaphragm aperture portion of the first diaphragm blade when the first diaphragm blade is moved to the exposure aperture portion, the incapable-of-covering area being where a portion of the exposure aperture portion is incapable of being covered; and a second diaphragm blade having a diaphragm aperture portion which restricts an intermediate diaphragm aperture, the second diaphragm blade being mounted to the base plate at a position near where the first diaphragm blade is mounted so that, by a driving pin of second driving means, the second diaphragm blade is reciprocatingly rotated to move to and away from the exposure aperture portion from substantially a same direction as the first diaphragm blade, the second diaphragm blade having a shape causing the second diaphragm blade to cover a whole area of the exposure aperture portion, differing from an area of the diaphragm aperture portion of the second diaphragm blade, when the second diaphragm blade is moved to the exposure aperture portion, wherein, when the first diaphragm blade is moved to the exposure aperture portion, the second diaphragm blade is also moved to the exposure aperture portion, so that the second diaphragm blade covers the incapable-of-covering area.