| 摘要 |
PURPOSE:To shorten the whole length of a lens and to simplify the constitution of the lens by arranging a water-proof glass consisting of a positive lens turning its convex face to the object side and a main lens having positive refractive force and capable of being moved in the optical axis direction so as to be focused successively from the object side. CONSTITUTION:The water-proof glass Ga consisting of the positive lens turning its convex face to the object side is watertightly and integrally held by a water- proof glass holder 12 and arranged on the image side of the glass Ga and the main lens GM having positive refractive force is held by a mirror barrel 16. The mirror barrel 16 is held by a shutter front plate 26 so as to be moved in the optical axis direction of the body, and when the main lens GM is moved in the optical axis direction together with the mirror barrel 16, focusing can be attained. Since it is unnecessary to adopt water-proof structure in case of moving the main lens GM, the constitution can be simplified.
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