| 摘要 |
1,194,814. Photographic exposure control. HONEYWELL Inc. Feb. 21, 1969 [Feb. 23, 1968], No.9489/69. Heading G2A. Light received through the objective lens of a camera is detected by two photo-cells, one being responsive to light from the whole image area, and the other to light from a part only of this area, and either cell can be connected to a meter by means of a change-over switch. The embodiment shown is a single lens reflex camera, the light received through the lens system 1 being reflected by the mirror 5 up through the focusing screen 12 into a pentaprism 14. This has two emergent faces, 14b and 14c. Behind face 14b is a collector lens 15 acting as a light path restricting means, so that the light passing therethrough is limited to that from a small circular area 16 on the screen 12, this being received by a first photo-cell 21. Behind face 14c is a further pair of collector lenses 23a, 23b, which collect light from the whole of the image area of screen 12, this being received by photo-cells 24a, 24b connected in series. Positioned between photo-cells 24a, 24b is an eyepiece lens 22, through which the whole area to be photographed can be viewed on the screen 12, and the central spot 16 identified. As shown, a change-over switch 31 can connect either cell 21 or the pair of cells 24a, 24b into the circuit of a meter 32, so that an exposure determination may be made based on the light received from the spot 16 only, or on light received from the entire image area. |
