[Chilliman]

Camera 40D: and maybe a stoopid question but if I don't ask I don't learn.
Regarding circular polarizers where you lose a stop or two of light when using one.

if am using AV mode, whatever the meter reading in the viewfinder for example F8 and shutterspeed 200 do I just reduce the F number down to the next stop F5.6 or F4 and not worry too much cos the shutter speed has increased to compensate for the smaller aperture.

[silkstone]

In any auto-exposure mode the camera will compensate for the filter because it uses through-the-lens metering. Just pretend it's a dull day and choose the appropriate aperture (AV mode) or shutter speed (Tv mode) as you would normally.

[AQ]

No just leave everything to the camera. In Av mode set the aperture to whatever you need as normal. The sensor in the camera will the register the reduced light because of the polariser and set the shutter speed to take account of that.

In short just use the camera as normal.

I assume you know that rotating the polariser on the front of the camera will give what different effects depending on you are pointing the camera at. reduced reflections from water or darkening skies

[Chilliman]

yeah I know about it rotating, I just wanted to check on the settings. I bought one today from Calumet normally 95 quid reduced to sale price 69 quid. First shot I took with it was underexposed but I opening the aperture more seemed to have a better exposure.

Some of my shots have been a bit flat and from what I've been told some could do with a bit punch to it, I'm hoping the CP will help a little in the right conditions.