Archived posting to the Leica Users Group, 1998/03/21
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Light rays diverge in a manner similar to that of a water wave. Light from the sun or a lamp consist of rays vibrating in many directions simultaneously. This is called unpolarized light. Light rays vibrating in only one direction are called linear polarized light. A linear polarizer, consists of a very fine foil grid (invisible to the eye) cemented between two pieces of glass. The grid only allows light vibrating parallel to the foil grid to pass through. Light rays vibrating perpendicular to the grid are blocked. Rays vibrating in intermediate directions are partially suppressed. Reflected light is polarized light. It is vibrating mostly in one direction. Looking (or photographing) through a polarizer, if turned correctly, will block reflected light. Turn the polarizer while looking through it to get the maximum effect. It removes the reflected blue sky from green leaves. Removes the white reflected haze leaving a deep blue sky, etc. A circular polarizer is like the above described linear polarizer, but has the addition of a 1/4 wave retarder, or delay, foil. This makes the polarized light coming through a circular polarizer, to look unpolarized to the Leica R camera meter cell, thus giving a proper meter reading. Information from B+W. Hope this helps. Jim