CAMERA

PURPOSE:To automatically make the quantity of light incident on a photo graphing lens nearly constant in a wide range by composing the photographing lens or a lens filter of a photochromic light transmitting body. CONSTITUTION:The photographing lens 7 is made up with the light transmitting body possessing photochromic effects. As the quantity of light incident on the photographing lens 7 increases, said lens 7 becomes darker in proportion to that increase. Conversely, as light quantity decreases, it becomes brighter. The photochromic light transmitting body comprising the photographing lens 7 employs glass containing photosensitive silver halide as colloid particles. The glass is produced as follows: glass containing alkali, alumina, borosilicate as constituents is heated and molten with silver chloride and silver bromide. After they are cooled, silver halide particles are deposited by reheating, etc. Without using any complicated, mechanical light quantity adjusting mechanism, light quantity in and out of rooms can lie within an appropriate range.