Show j V 1 f j cS' cS I mod ond Registers the L Light With a a. mechanical mechanical means means for fol determining deter deter mining the proper exposure of photographic photographic photo photo- photographic graphic plates almost the whole cy cycle le leot of ot photography is reduced to a definite definite nite mechanical basis It is true that the op operator may still display individual individual indi indi- vidual aptitude In the artistic composition composition composition compo compo- of his subjects but aside from this all ll the other operations ns are more or less positive The latest photographic photographic photo photo- photographic graphic exposure meter Is based on a principle that al already eady has been applied applied ap ap- plied to to- toa a meter for determining the j ro Photographic Exposure Meter illumination nation furnished by any artificial art arti facial source such as electrical or gas light tIght It is based on the peculiar pr property of the eye of being able to distinguish characters such as figures or letters within a wide range range However However However How How- ever on approaching the extreme lower low low- er limits of luminous visibility the change Is qu quite te abrupt that is to say the eye adapts itself to almost any d degree de do- gree of illumination but the lower I limit is very well established As applied applied applied ap ap- plied to a photographic exposure meter there Is a casing provided with witha a graduated light inlet and eye open ing A sleeve Is adjustable over this opening The area of unobstructed opening is indicated on ona a graduated scale or table Within this chamber there are visual figures Upon looking into the device through the eye leye opening open ing the slide over the window is adjusted adjusted ad ad- until the illumination appears appear to be equal to that shown on the ground glass of the camera exposed under similar conditions The scale reading then indicates the intensity of f the illumination and the length Is thereby definitely fixed |