GB416304A - Improvements in or relating to adjustable iris diaphragms mounted within photographic objectives - Google Patents

Abstract

416,304. Iris diaphragms. LEITZ GES., E., Optical Works, Wetzlar, Germany. June 29, 1934, No. 19242. Convention date, July 17, 1933. [Class 97 (i).] In an adjustable iris diaphragm provided with an adjusting ring F and mounted within a photographic objective for use in black-andwhite photography and in colour photography employing a lenticular film and a multiple strip filter, the diaphragm opening is of polygonal form and the ring F has a setting mark or retaining catch to facilitate adjustment of the diaphragm into the position suitable for colour photography, namely that in which equal colour component parts are cut out from the filter. The diaphragm comprises leaves C<1>, C<2>-C<12> pivoted by pins D<1> on a fixed support. The other ends of the leaves are provided with pins E<1> moving in slots E<2> in a movable ring E secured to the adjusting ring F by a screw F<1>. In the construction shown alternate leaves have straight edges and collaborate in forming the hexagonal diaphragm opening, the remaining leaves serving to cover the gaps formed at the back of the first mentioned leaves during the closing of the opening. This opening may also be square or of other polygonal form. The leaves may move on a spherical surface to reduce vignetting to a minimum.