I heard that when using a polarizer, you should not aim your camera to the sky and adjust your CPL to get the darkest sky (it is what I have been doing). What you should do is to look at something with reflection and rotate your CPL to minimize the reflection from the subject. How do you use it? What I dont get is why cannot you just get a dark sky in the viewfinder, which will turn out to be a very blue sky in the image. Someone said it is wrong. But I dont know why. The other thing is that when using CPL, why do you do a negative exposure compensation? I assume you are metering with the CPL on the lens, and the CPL already darkens what the camera sees, so you should get a correct metering reading for the CPL-added scene. It is mentioned here in this video: If anyone can provide a very good source illustrating how to correctly use a CPL, that would be also very appreciated. Thanks for reading my questions and your input.