| 摘要 |
PURPOSE:To vary a light distribution characteristic in the water to attach importance to a short distance without being hindered at all in air, and to execute a photographing whose light distribution is more uniform, by inclining a front protector of a stroboscope by a specified angle in the photographing optical axis direction. CONSTITUTION:In a water proof camera containing a stroboscope, and protector of the stroboscope is inclined so that the optical axis of a photographic lens 6 crosses the normal of a protector 4 of said stroboscope. Denoting the distance from the center of the photographic lens to the protector of the stroboscope as l, a distance from a film surface to an object to be photographed as L, l/L, as an angle theta derived from a trigonometrical function table a refractive index of air as n, and a refractive index of water as n3, then, an inclined angle alpha of the stroboscope satisfies an expression tanalpha=sintheta/(costheta-n1/n3), by which a light distribution characteristic not only in the air put in the water is raised. |
