Archived posting to the Leica Users Group, 1998/06/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>Then I thought perhaps polarisers repeat >every 180 deg, given the physics of polarised light. Is this so and in this >case why do Leica go to so much trouble to rotate the filter correctly in >their swinging device? Yes, polarizers repeat every 180 deg. I don't understand how the Leica polarizer is going to too much trouble. They seem to be taking a logical route. >Also, on another tack what is a circular polariser? >If orhtogonality of polarised light is required for cancellation as I >understand it what is a circular polariser doing and how does it , for >example cancel a reflection? At any given point the circular polarizer passes only light travelling in one vibration direction. The orientation of this one direction changes as you move around the filter, but the effect on the imaged passing through the lens is the same as in linear polarizers: randomly scattered light is reduced as so glare is cut down and skies 45 deg. from the sun's position are visibly darkened. In technical applications the lack of linear polarized light will make a difference, but for general photographic use the circular polarizers are just as effective. - -Charlie