circular polarizer and cross polarizizing art work

[michaelnotar]

im shooting art and using the cross polarization technique with my lights. my camera is manual focus and i will be doing just that. the lights will have linear polarizers on them and the lens will have a linear polarizer too in the opposite direction. this works fine, the question is does the circular polarizer on the lens change anything? i found my circ polarizer a few days ago, havent used it in a while, ive been shooting 4x5 for awhile. thanks

[Doug_Kerr]

Hi, Michael,

Originally Posted by michaelnotar

im shooting art and using the cross polarization technique with my lights. my camera is manual focus and i will be doing just that. the lights will have linear polarizers on them and the lens will have a linear polarizer too in the opposite direction. this works fine, the question is does the circular polarizer on the lens change anything? i found my circ polarizer a few days ago, havent used it in a while, ive been shooting 4x5 for awhile. thanks

There should be no change in basic photographic performance with the use of a circular, rather than linear, polarizer on the camera, other than that the reducion in expsure may be slightly different.

Both work the same as a polarization "analyzer", selectively attenuating components in the light from the scene having the "undesired" direction of polarization.

The difference occurs behind the polarizer. With a linear polarizer, the light passed through to the imaging system is linearly polarized, while with a circular polarizer, it is circularly polarized. In the latter case, for the purposes generally of interest to us,m that light behaves as "non-polarized".

The significance is of course that in a camera in which the light encounters a partially-reflective mirror on its way to the exposure metering detectors, if that light is polarized (as in the case of a linear polarizer on the camera), the orientation of the polarizer can affect the "calibration" of the exposure metering system, leading to inconsistent exposure determinations.

[BobSmith]

I do a lot of cross polarized lighting copy work. The one time I tried it with a circular polarizer on the camera it caused all sorts of color problems. You could see pretty dramatic color shifts as the filter was rotated on the camera. I don't know if that was caused by the particular combination of light and camera filters I was using or if it was a problem with circular filters in general. I went back to linear polarizers on the camera and haven't had any issues since. If the circular works well for you, please let us know.

Bob Smith