50mm summicron, polarizing filter, and Luna pro light meter

[patrickrucker1]

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hi, thank you for the time. I have searched for an answer, but cannot find one.

hi, thank you for the time. I have searched for an answer, but cannot find one.

If I want to use a polarizing filter for my Leica  M3.

would it be reasonable to put the polarizing filter in front of my Luna pro light meter and see how much light is attenuated  ? After I adjust the light meter, Will this value be accurate for the brightest of lights and darkest of lights? I.e. is it a constant attenuation percent of the incoming light? I assume that it 

Thank you!!

Pat.

[UliWer]

The effect of a polarizing filter depends on its angle towards the sun or if you want to reduce reflections: towards the reflecting object. With an M you cannot control its effect as long as the polarizer isn’t in front of the viewfinder or in a position where you can look through it directly. Therefore there are special „swing out“ constructions which allow you to control the effect through the viewfinder in a position of 180° to the lens then you swing it back in front of the lens, and the effect on the photo will be the same as you saw it though the viewfinder.

So you would have to measure the light with your lightmeter through the filter in its swung out position. I fear this will be very clumsy if not impossible to handle. So it might be easier to follow a rule of thumbs: if you use the polarizer with max. effect you should use your measured exposure multiplied by 3. So Instead of 1/500 at f/5.6 you should use 1/125 at f5.6 or perhaps f/6.3, or use 1/500 at f/2.8.   In a position with less than max. effect you use the measured exposure multiplied by 2 and so on. Trial and error by making a sequel of photos with different exposures (and taking notes which values you used) will help a lot.

Edited 21 hours ago by UliWer