| 摘要 |
The present invention relates to apparatus for photography under water, and is directed generally to the complete or partial elimination of the fluid-tight bushings inevitably necessitated for the controls of such apparatus, by transferring to the exterior of the fluid-tight casing of the apparatus, the various devices necessary for the control of exposure of the light sensitive material. The diaphragm of the camera lens is arranged in front of the lens, outside the fluid-tight casing, and is therefore under water when the apparatus is immersed. This permits the variation of the aperture and the exposure time without need of access to the interior of the casing. Also, the lens is produced in the form of a thick meniscus with a concave inlet diopter, the convex diopter of the whole unit being added by the liquid immersion medium itself. This lens has the advantage, apart from the transfer of the diaphragm to the exterior of the casing, that it has great resistance to pressure. The invention provides an under-water photographic apparatus of low production cost and high reliability, having only one fluid-tight bushing for the forward movement of the film, and finds its application both in the form of special devices such as cameras for under water surveillance for which reliable fluid-tightness under high pressure is important and in the form of apparatus intended for a large public.
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