| 摘要 |
1,231,071. Exposure control. NIPPON KOGAKU K.K. April 19, 1968 [April 20, 1967(2)], No.18691/68. Heading G2A. In a single lens reflex camera having interchangeable objectives, the photo-cell of an exposure meter, which is positioned outside the light path through the objective, has in front of it a variable aperture diaphragm which is linked to the main objective diaphragm so that the two move together. As shown, the objective lens 1 has diaphragm blades 2 which are set to a predetermined value by manually adjusting a ring 4. The diaphragm remains open at full aperture until it is closed to the pre-set value, just before exposure, by rotation of a ring 3. Part of the light admitted by lens 1 is reflected from a semi-transparent mirror 7 to a focusing plate 8, and part passes through and is reflected by a concave mirror 11 to fall on the photo-sensitive element 12 of a light meter. In front of this is a diaphragm 13 which is linked to ring 4 by an interlocking ring 14. (Mirrors 7 and 11 can swing together out of the light path to the film 10.) It is thus not necessary to adjust the sensitivity of the photo-cell every time the lens is changed. The relationship between the movements is such that an alteration of ring 4 by one stop produces an alteration in diaphragm 13 of one stop. Figs. 4 and 6 (not shown) illustrate arrangements having different modifications of the light path to the photo-cell, which may additionally have a field stop and a lens. |
