Will the exposure compnesation for a polarizer vary depending on the degree on polarization? I would think yes. How then do I calculate this if I am using an M4? Is the only way to guess/bracket?

-- enrique munoz (dem331@yahoo.com), March 14, 2002

Answers

Yes, it does vary slightly - I have never worried about this and certainly if using neg. film just add 2 stops to the exposure.

-- Giles Poilu (giles@monpoilu.icom43.net), March 14, 2002.

Point your handheld meter through your polarising filter. Hold the polarisng filter at the same orientation it is on the lens.

-- John Collier (jbcollier@powersurfr.com), March 14, 2002.

if it's a linear polarizer, the loss of light is strongly dependent upon orientation. Not so if it's a circular polarizer. A good guess for the maximum degree of polarization would be 1.5-2 stops. I think you want to be on the under-exposure (slightly) rather than over- exposure side, with a polarizing filter, since over-exposure will reduce the impact of the polarizer.

-- Eliot (erosen@lij.edu), March 14, 2002.

if it's a linear polarizer, the loss of light is strongly dependent upon orientation. Not so if it's a circular polarizer.

Please explain. I've used a circular polarizer with in-camera and handheld meters, and the light loss is quite dependent on orientation (depending, of course, on the amount of polarized light in the scene).

-- Mike Dixon (mike@mikedixonphotography.com), March 14, 2002.

The best solution for Leica M's w/o TTL metering is to use an MR/MR-4 meter and the Leica swing-out polarizer. You swing the polarizer up in front of the meter, rotate for desired effect, meter the scene and return the filter to the front of the lens. It's easier than it sounds and really does work.

-- Bud (budcook@attglobal.net), March 14, 2002.

Mike. I meant to say "not so 'much' if it is a circular polarizer. I only use the linear polarizer. I thought cirular polarizers produce less darkening than linear polarizers. I left out the word 'much'.

-- Eliot (erosen@lij.edu), March 14, 2002.

Thanks for your comments. I am a bit confused about the circular and linear being different in terms of exposure compensation, specially since I have both (in two different filter sizes). I guess I will make some trial exposures.

-- enrique munoz (dem331@yahoo.com), March 15, 2002.