Circular ND Filters

[bevan2004]

Hi all,

Can anyone explain to me the benefits of using a circular polarising Neutral density filter as opposed to the graduated ND filters? I understand the reasons for using the graduated filters, but not sure what the purpose of the circular ones are, even though I bet they are very useful.

cheers
Bevan

[coffee]

Circular ND filters are very usful if you can't slow the shutter down enough due to too much light, like bright sun. For example, if I was shooting a waterfall and wanted to use a longer shutter to make the water silky, but there is so much light you can't get the shutter slowed down enough, you might throw on one/more ND's to stop the light getting through the lens by 1-8 or more stops. Then, you can get a slower shutter.

[jerryph]

ND filters cut light be a preset amount. Graduated ND filters cut different amounts off in varying amounts from the top of the filter surface and less as one goes lower.

CPOL filters have an anti-hazing and anti-glare effects tossed in that ND filters do not.

[DoctorJazz]

Is there ever a situation where you would use both ND and CPol filters simultaneously? Would that reduce light too much?