Circular Polarizer: Yay or Nay?

[iskibc]

I've had mixed results using my polarizer for skiing photos. I usually only use it on bluebird days, or late season when the light is stronger during the mid hours of the day.

When is it best to use a polarizer? How do you adjust your camera settings differently when using a polarizer? I'm having issues with pics coming out too dark or too contrasty when using my polarizer. I'm not really making any changes to my settings. Should I?

Thanks.

[pechelman]

Circular polarizers are only needed for some\most autofocus sensors as it screws with how they work. Theyre really no different than whats done to the image by a normal\linear Polarizing filter.

Use a CP when there is lots of snow surface glare or a lot in the sky. Generally you can saturate the sky a good bit the sun is in the right place.

If you stick the CP on the end of the lens, and then meter, your camera adjusts accordingly and you shouldnt have to do anything.

Also, I find that a lot of people use CP's as an on\off switch and dont ever use it to leave some glare like on the surface of a lake. Sometimes thats nice, but other times it looks unnatural imo.

If youre having trouble with contrast, I might suggest using a lower film speed, pulling the film, or probably in your case, using a slower ISO setting. (if the same rules apply to digicams)

Too dark, all I can say is to use an exposure compensation on what your meter says by whatever you think they need to be.

[Summit]

i only use on bluebird... i don't usually use it for skiing action shots that much because the thing sucks up 2.5 stops of light that force me to up the ISO to still freeze the action (which increases noise and decreases dynamic range, not good for contrasty snow scenes).

You have to be very carefull with the metering with the circ-pol... matrix meters can be confused by what they read as dark skies. You can't just sunny f/16 and go either.

The problem is that the filter factor of a polarizer varies with the polarity of the incoming light relative to the filter angle and can be anywhere from 1.3 to 3.6 but is usually around 2.3.

BUT... if the shot calls for it, w00t it can make a hudge difference (most often in wide angle for that dramatic dark sky)

I find them most usefull for scenics... they can cut scatter glare, make for dramatic skies with contrasty clouds, and can control reflections. Unfortunately, they are most effective depending on your shoot-sun angle (more inline with the sun = less effect) and as we all know the mountain often dictates our shooting lines.

[pechelman]

The problem is that the filter factor of a polarizer varies with the polarity of the incoming light relative to the filter angle and can be anywhere from 1.3 to 3.6 but is usually around 2.3.

right

but if youre metering through the polarizer doesnt it take it into account?

am I wrong in not thinking that the camera takes into account this varying filter factor on polarizers?

Its a bit more tricky when you have to use a polarizer on a camera that doesnt have a meter because of this. Generally I just rotate the filter until I like what I see, hold the filter at that angular orientation, hold up my hand held meter, and meter through it, and ive always gotten the exposure I needed. Granted this was on an old russian 6x9 bellows camera, but Id figure the principle would be the same.

[AstroPax]

but if youre metering through the polarizer doesnt it take it into account?

Of course it does.

On a similar note, one of the the biggest mistakes that photographers make when using a circular polarizer is to compose the shot, half-press the shutter, and then rotate the polarizer *after* the exposure is set.

[mtbakerskier]

For what its worth, I never ever use a polariser when shooting skiing.

[truth]

I tend to only use a CP when I really want to bring out details in clouds or am looking for a certain effect with reflective surfaces. I feel it tends to make an empty blue sky a bit too blue most of the time.