Question about polarizers

[OldFox]

I am new to polarizers. Here is a list of Hoya's that found out from one site for my Canon 17-40L USM which uses 77m filters. The prices range from $40 to $140. Other brands have somewhat different types as well.

- it seems that there are at least 2 or 3 kinds (circular/linear/conversion) of polarizers, how do they differ from each other?

- any suggestions for my lens? Is the extra $100 worthwhile?

- any good reading somewhere?

- (sorry about the dumb questions)

77mm (Moose) Warm Circular Polarizer Glass Filter
77mm Circular Polarizer (HMC) Multi-Coated Glass Filter
77mm Circular Polarizer (S-HMC) Super Multi-Coated Glass Filter - Thin
77mm Circular Polarizer / UV Haze (HMC) Multi-Coated Glass Filter - Ultra Thin
77mm Circular Polarizer Glass Filter
77mm Linear Polarizer Glass Filter
77mm Polarizer / Conversion Glass Filter

[Roger_Cavanagh]

Can't help you choose, except to say I wouldn't put cheap filters in front of good glass.

I've some links to good articles on filters here:

http://www.pixelpixel.org/links-01.htm#Filters

Regards,

[CyberDyneSystems]

As far as Circular vs. linear,. this is effected by the actual camera used (you did not mention)

Circular polarizers are needed on most Canon Autofocus cameras as the linear polarizer may adversely effect the autofocus of the camera (including 10D and I assume Drebel)

So I'm pretty sure that will narrow it down to Circular.

I'm pretty sure I have this filter;

"77mm Circular Polarizer Glass Filter "

And it seems to work very well on my 10D on a number of lenses I own with 77mm threads.

[rdenney]

oldfox wrote:

77mm (Moose) Warm Circular Polarizer Glass Filter
77mm Circular Polarizer (HMC) Multi-Coated Glass Filter
77mm Circular Polarizer (S-HMC) Super Multi-Coated Glass Filter - Thin
77mm Circular Polarizer / UV Haze (HMC) Multi-Coated Glass Filter - Ultra Thin
77mm Circular Polarizer Glass Filter
77mm Linear Polarizer Glass Filter
77mm Polarizer / Conversion Glass Filter


Of these, I would use the S-HMC thin circular polarizer. Thick filters sometimes degrade wide-angle lens performance because of the shallow angle of entering light. And there's no sense in spending more for multicoated lenses and then put a flary piece of marginally coated glass in front of it.

Canon cameras have always require circular polarizers because of the beam-splitting approach they use to move light to meter cells.

And you don't need a warming filter. If you want a warming effect, shoot RAW and adjust the white balance when you convert. A bluer white balance will give you the same effect as a warming filter. The filters are designed for folks who don't like the color balance of their otherwise favorite slide film. Not needed on a DSLR.

Rick "who hand-holds a Bronica 95mm polarizer in front of the lens when he needs it" Denney

[OldFox]

Thanks for the info, especially for the links.

I forgot the mention the camera, it is 10D.