| 摘要 |
PURPOSE:To perform autofocusing in a TTL system without imparing the merit of a compact camera which is small-sized and low-priced by providing a half prism between the backmost position of a photographing lens and a shutter. CONSTITUTION:A luminous flux for range-finding which is transmitted through a photographing lens 1 is bent before it is transmitted through the shutter 4, that is, on the objective side of the shutter 4, by the half prism 3. Then, it does not pass the shutter 4 but bypasses it to be guided to a focus detecting device 2. In such a case, the luminous flux is allowed to reach a film surface because the half prism 3 transmits the photographing luminous flux. Even though the TTL system is adopted in spite of a lens shutter type camera, the action of the shutter combined with a diaphragm in the case of autofocusing is made unnecessary and a mechanism for performing the above action is also made unnecessary, thereby miniaturizing the camera itself and simplifying the mechanism. |
