Originally Posted by slickShooter
I'd rather not scratch my lense by getting to close so I'd prefer to leave my polarized filter on the camera......it doesn't say in the manual but I read I can adjust the "power" of the polarizer by turning it. (it spins on the end farthest from the camera).Does this mean I could turn it "off" or close to it and just use it as a lense guard so to speak. Thing i don't understand is it doesnt seem to stop spinning so how do I know what setting its on?
A polarizing filter usually acts as a 3X neutral density filter as well as a polarizer. You canít affect the light loss by rotating the lens. By cutting the light you are allowing to get to the lens to a third of what it would be if you didnít have the filter you have increased your dependency on flash or a tripod.
Polarized light vibrates in a specific direction rather than randomly. The polarizer just blocks those rays that are polarized if you rotate it the right way. Take the filter off and look through it at reflections off water or at a blue sky. You will notice more effect in certain directions. It isnít a setting but an effect you are getting rotating the filter.
Go into a store selling polarized sunglasses and pick up two pair. Rotate them to 90 degrees from each other and look through them. They will block most of the light because one is blocking light polarized vertically and the other blocking light polarized horizontally.
I took these pictures early this year using my polarized sunglasses as a filter. The bottom photo is with the polarizer. Notice the difference in the reflections from the rear window and especially the trim: http://www.pbase.com/image/15070822
I would have gotten no effect from the polarized lens if I rotated it 90 degrees, but I would have still cut the light.
A polarizing filter makes a lousy general purpose lens protector because it cuts out 2/3 of the light. Get a UV filter for that purpose.