Reading books and articles online, a circular polarizer (CPL) is very often described as Gods gift to mankind, it reduce glare, gives the sky more definition, and over all enriches, the colors in your photographs. As long as you have a polarizer, you are golden.
If I Could Turn Back Time - Volume SeventeenNo CPL I’m telling you that you are wrong, or more correctly, if you have a camera that doesn’t handle high ISO very well, you do not want to get a CPL because you will get noise issues. Why? Because polarizers can steal up to three stops of light. This means that, if you for example are at ISO 200 with a shutter and aperture that you are happy with and you mount a CPL that steals three stops of light, you need to dial in ISO 1600 in order to be able to keep your shutter and aperture settings !
I know what you are saying, ISO 1600 is nothing these days, in most cases you are right. Three stops is a exaggeration, two stops are more like it, again in some cases, you are right.
The bottom line….before you consider buying a CPL. Ask yourself, in what situations will you be using it and at what ISO are you normally at in those situations ? At what ISO levels are you comfortable? In other words, will you get a noise penalty when using a CPL and if so, is it worth it ?
If you found this post interesting, I recommend that you to read the excellent article “Understanding ISO, Shutter Speed and Aperture – A Beginner’s Guide”.