Compensation for polarizers

Question

is compensation necessary for polarizers if yes by how much ,i use a cpl for nikon d 50.

Answer 1

Well the above answers are not technically correct.

Assuming that you aren't using the in camera meter or on automatic then yes you do need to be aware of the compensation factor.(yes there are reason why you shouldn't  see below)

Now this factor changes depending on how much you choose to polarize.

Assuming that you have the standard polarizer it should be close to 2 1/2 stops when the polarizer is in the full position. Lets say you want the sky to be darker but not completely dark. then you wont have the polarizer in a full position. In this case the EV will be less.

Now this is why you do not to blindly follow the in camera meter. Lets say you are doing a Black and white shot with a red filter.

Lets also say you are taking a picture that includes a lot of sky with Puffy white clouds and water.  (Think Ansel Adams)

Now if you follow the in camera Meter it will see the sky and water as being too dark and it will want you to open up much more than the EV value of the filter.(BAD!)

The whole point of using the polarizer in this instance is to get the dark dramatic skies! You do not want to bring the over all picture back to midtones,

So lets say you only have an in Camera meter. The best way to get the

exposure you want is have the base exposure first. IE the proper exposure without the Polarizer and other filters. Then add the other filters and adjust the EV. (EV=exposure Value) Most likely 2.5 stops.

When you buy your filters don't throw out that paper that comes with them. It will give you the exact EV for each filter.

Note they do make a few polarizers with different EV values.

Answer 2

No ...

Your exposure meter in the camera takes care of that

Exposure compensation is something done when using an external light meter ... Who told you about that?

Answer 3

Your TTL meter in your camera will adjust for you.

However, a polarizer will lose about 2 stops.... so if you are in low light situations, take it off.