Hoya Pro1D Circular Polarising Filter tips?

[tanalasta]

I have a Hoya Pro1D Circular polarising filter and just had a few questions:
- Does anyone know roughly how many stops (similar to a ND filter) of light it affects?
- In general, do people set EV compensation when using a polarising filter?
- What is the best metering method- spot, circle or matrix do people tend to use with the PL filter?

Any tips on the best use for the filter would be appreciated, as well as in-camera settings. I have it attached to a 55-200mm VR kit lens at the moment, which is a bit slow (especially with the PL filter attached).

Is it generally best to remove the filter if I use it for portrait/flowers? Or leave it on if I am outdoors?

An example of a photo I shot with the filter and the lens:
http://gallery.me.com/kevin.kwan/100097/DSC_0227/web.jpg?ver=12560206000001

[arthurking83]

The filters ND rating is going to vary a little, depending on the amount of polarisation you're going to use.
So the rotation of the filter will affect the exposure value to a certain degree.

generally speaking you may see between 1-2stops of exposure loss.

Also depending on the time of day you shoot too.
I get more vignetting late afternoon if I'm using the Pol.. which is blindingly obvious on my 10mm lens, so it'd darkening the corners more so than when I use it in brighter light.

Also it can affect the exposure value of various parts of a scene so differently that to put a standard ND EV value on it can be misleading!

testing the average exposure hit is quite easy to do yourself.. and see how much it affects the scene(in an average sense).

use a white wall, and using aperture priority mode. set the camera to spot metering and take a EV reading.
If the shutter speed says 1/80 for a neutral exposure, then that's your starting point.
(depending on the light!!) add the CPL to the lens, and then take a reading again. if the shutter speed drop to 1/40 for the same aperture, then your CPL is losing 1 stop of light :D easy!
Also!! depending on the light source and the reflectance of the white wall(gloss or low sheen).. rotate the CPL and see if it affects the scene again! in spot mode, almost certainly unlikely, especially if you're using the central spot metering zone.
But if your camera has the ability to meter deep into the corners of the frame(D300 has quite a large focus/metering area relative to the frame! :th3:), chances are that you may see more variance in the loss of light as you rotate.. and depending on the FOV(focal length of the lens).. wider lenses take more of a hit into the corners as they CPL is roated to produce maximum polarization effect.