| 摘要 |
PURPOSE:To reduce the cost of a device by using a photosensitive film as the material of a focus plate, and aligning the observing points of both of a light measurement system and a finder system with each other without adjusting their optical axes. CONSTITUTION:Luminous flux from a light source 12 passes through a photoconductor 11 to illuminate a visual field control plate 2. This plate 2 is provided with a reflection part 2b at the peripheral edge of an opening 2a, its outside is a black absorbing surface, and the reflection part 2b reflects the luminous flux to a concave mirror 1. This luminous flux travels in the opposite direction from light during light measurement and is converged on a screen 20 provided at a point 10 to be measured to form the image 20b of the plate 2, thereby forming the ring image 20a of the reflection part 2b. The inside of this image 20a is a measurement point determined by the opening 2a and the luminous flux forming the image 20a is reflected by the screen 20 and passes through 45 deg. mirrors 5 and 6, etc., to form the ring image 8a on the focus plate 8 of a thermally activated photosensitive film. Those rings 2b, 20a, and 8a are in optical conjugate relation and the image 8a on the plate 8 is printed on a photosensitive layer to form a measurement point mark.
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