| 摘要 |
<p>PURPOSE:To switch a photometric optical system by a simple mechanism even in case when there is no room at the side of a body, by moving 1 piece or plural pieces of optical systems in the vertical direction against an optical axis of the photometric optical system placed in front of a photodetector, so that a focal distance of the photometric optical system concerned can be varied. CONSTITUTION:The first optical element 5a and the second optical element 5b are mutually of the same shape, and each opposed surface has a shape for complementing each other so that thickness of one end becomes thin and thickness of the other end becomes thick. When one or both of said first optical element 5a and second optical element 5b are moved, and a distance between both the elements 5a, 5b is separated to the maximum, each thin part of one end of the optical elements 5a, 5b is positioned in front of a photodetector 4, and partial photometry whose photometric range is narrow can be executed. On the contrary, when the distance between both the elements 5a, 5b is made to approach to the maximum, mean photometry can be executed.</p> |
