Circular polarizor for wide angles

I'm using a sigma 77mm cir polarizor on my canon 10-22 wide angle lens withless than stellar results. only a very small area seems to be affected. Is this common or is the polarizor to blame? Thanks for any help.Dean

Dean - The amount of polarization is dependent on the angle of light rays to the polarizer, with the strongest effect occurring when the light is around an angle of 90 degrees to the filter. So there could be two things going on :

1) You're using the polarizer with light coming directly from in front or behind. This would affect any lens and lessen the effects of the polarizer.
2) On a very wide angle lens such as the 10-22, as you move across the frame the angle of the light to the filter changes a lot, resulting in unevenness. This is usually most visible in skies as a darker patch that gets progressively lighter as you move away from it.

If #2 is your problem, the usual thing to try is turning the polarizer so that the effect is lessened but you still get some polarization.

I've just about stopped using polarizers on wide angle lenses if there's much sky in the shot. They're immensely useful for reflection control, so when I need that I'll work to frame with as little sky as possible.

The alternative for me when lots of sky is needed in a shot is to use Selective Color in post processing. It's under Image->Adjustment. Go to the blue, cyan, white and neutral channels and use the Black slider in each. You can do an amazing job of "polarizing" skies after the fact.

Conversely, if you have an image that you decide was shot with too much effect from a polarizing filter on the lens, you can use the same Selective Color controls to "tame" the effect.

I'm with Hank.
However, if a polarizer can help with the foreground, then I'll shoot one image with it on and then one immediately after with it off to keep from buggering up the skies. Then it's just a matter of simply blending those images later.

I'm also in that camp and I'll add that it doesn't matter whether you're using linear or circular polarizers. Ultra-wide angle lenses can have angle of view around 85 degrees while polarizers are going to have their strongest effect at 90 degrees to the sun and less effect quickly at other angles. I work with the same methods as Hank and John. Make the sky a smaller portion of the composition, use a longer lens or shoot one at full polarization and then one with the filter turned 90 degrees for minimum polarization. Another alternative is to back off the full polarization at wide angles. You can still get some help cutting reflections from leaves and deepen the sky blue a bit, but the sky doesn't get the black-hole-sun look.

+1 to what Hank said. Image blending works, too.

Thanks for everyones replies. I'm thinking I'll just give -up the polarizor on the wide end.

Keep it in the bag Dean. In some locations and shots it's really useful. But as you observe, it's not a "universal" tool.

I disagree with the others. You can learn to avoid the sky discontinuities. Besides reflection control, the haze reduction and color enhancement is a big advantage, IMO. Also, while there are other protective filters, none of them are quite as useful as a CP, and when i smashed two thin CPs on my last photo shoot, i was extremely grateful that my lens wasn't taking the impact! I use a polarizer probably 80+ % of the time.

The only reason for a circular VS a lilnear polarizer is because of the construction of the camera. If you have semi transparent mirrors in a camera system (usually because of a metering system), with a linear it will sometime be abosolutely visually opaque leaving some very strange exposures.

Lynn