To regulate the maximum aperture diameter of a shutter vane that copes with the luminance of a subject of a wide area.
A regulating lever 56 is rotated between a regulating position where a contact part 71 is inserted into the turning locus of a shutter vane 41 and a non-regulating position, where it is retracted from the locus. The regulating lever is kept forced at a neutral position by a torsion spring 72. When the regulating lever 56 is at the neutral position, a projecting member 45 projects into the rotation locus of a projecting part 45 disposed on a rotating cylinder 24. When focusing takes places during exposure without regulating an aperture, the rotating cylinder 24 is rotated, in one direction where the projecting part 45 is engaged with the projecting member 43 from one end 45a, and thereby the regulating lever 56 is rotated to the non-regulating position. Focus is moved, while the rotatory cylinder 24 is rotated within an engagement-retaining range. When focusing takes places during exposure while the aperture is regulated, the rotating cylinder 24 is rotated, until the projecting part 45 is passed through the projecting member 43. Thereafter, the rotating cylinder 24 is rotated in the reverse direction, the projecting member 45 is engaged with the projecting member 43 from the other end 45b, thereby the regulating lever 56 is rotated to the regulating position; and the focus is moved, while the rotatory cylinder 24 is rotated within the engagement-retaining range.
KANEKO YUKIHIRO
NISHIMURA TOSHIHARU
