Circular Polarizer

[bgclight]

Hi Bob:

I have the T1i with the 17-55mm 2.8 lens I plan to use the  B + W 77mm Circular Polarizer with it. (Just ordered) I currently have a UV filter on the lens for protection. Do you leave the polarizer on all the time or only put it on when you think you need it? Is there any adjusting with the polarizer or does it sync with the auto focus?

Sorry for the dumb questions. The T1i with the 17-55 lens is by far the best combination I have used so far.

Thanks for your help, B.G.C Virginia Beach, VA

[KeithB]

Since the polarizer will cost you about over a stop of exposure, you usually put it on when you need it.  (Though it is a pretty good - though not very dark - Neutral Density filter if you want to increase exposure a bit for flowing water effects and such.)

It does not need to be "synced" - Auto focus will always work with the polarizer in place.

However, the poarizer needs to be rotated to a particular angle for best effect, so you don't want to just leave it on the camera with some random rotation.  It will probably be used to best effect for landscapes, and should be rotated to get you the bluest sky.

ETA:
Here is Bob's article on polarizers:
http://www.bobatkins.com/photography/tutorials/polarizers.html

[bgclight]

Thanks KeithB

Your answer was veryh helpful as well as the link to Bob's original answer re: polarizers.

BGC

[whizkid]

Just don't have both filters on at the same time.