Lens-fitted photographic flim unit and exposure aperture size changing device therefor

摘要

A lens-fitted photographic film unit whose film surface disposed behind an exposure aperture is forwardly concave along the longitudinal direction of the film strip so as to correct distortion by the taking lens. The unit has an exposure aperture size changing device constituted of a manually actuated photography mode changing member for selecting either a standard photography mode for forming a standard size picture frame, or a special photography mode in which a special size picture frame smaller than the standard size picture frame may be formed. A pair of aperture masking plates is movable into margins of the exposure aperture, for masking out parts of the exposure aperture. The masking plates have such shapes that, if images of the aperture masking plates are projected onto a plane perpendicular to an optical axis of the taking lens in the masking position, the images have concave top and bottom margins, so that the special size picture frame has a rectangular shape when the images of the masking plates are projected on that concave film surface instead of on that perpendicular plane.