Another polarizer question

[Harry Settle]

Since circular polarizers were developed, primarily, to acommadate lenses that turn when focusing. . . is there a special need for using circular vs. linear polarizers on the end of the lens for digital cameras?

[KennyG]

Actually, circular polarizers were developed for cameras with TTL (Through The Lens) metering, nothing at all to do with rotating lenses.

You should use circular polarizers.

[c0ntr0lz]

was at the car show the other day
and i was taking a photo of this car that had a piece of paper on the dash
when i adjusted my CP....


http://ctrlzproduction.com/images/carz/paper_impala.jpg



as you can see the paper was no longer there
and i thought about shooting one with the paper just so i could show it off when ques were asked like this

[SWPhotoImaging]

The heck with the paper, or the ploarizer . . . I want the Impala! That's a gorgeous ('59?) hardtop!

[93octane]

yeah nice impala. :D

[Lamplight]

Mmm...'61 Impala. :drool:

I was thinking that it would be difficult to use a polarizing filter on a lens that rotated when focusing. Unless maybe you focused and then adjusted the filter, but I don't know. ??? I have one I can use on my 50mm 1.8, but the end of that lens does not rotate.

[Harry Settle]

It's got to be more than just the TTL metering, because we've been shooting with film that way with linears for years. I might bite on ETTL if that's the case. I'm not arguing with anyone, just curious.

[c0ntr0lz]

thanks guys
yeah it was a beauty
so is a linear one that you dont have to rotate?

[KennyG]

You have to rotate both types of filter. A linear polarizer is not suitable for TTL AF due to the way it effects the incoming light.

May I suggest you read this:
http://www.luminous-landscape.com/tutorials/polarizers.shtml

Or this:
http://w1.541.telia.com/~u54105795/filters_faq/filters.html#polq2

Or even this:
http://www.outdoorphotographer.com/content/pastissues/2001/july/polarizing.html

[Harry Settle]

Got it. Good links. However, correct me if I'm wrong, aren't linear polarizers what we have been using all along? At least up until the last couple of years.

[robertwgross]

I switched from a different camera brand to Canon in 1997. At that time, I discovered that my old linear polarizer didn't work right on Canon. Then I discovered that circular polarizers cost more than linear ones.

---Bob Gross---

[kufel]

linear polarizers affect autofocusing mainly, TTL to some effect as well, but AF is the main reason that we have to use circulars. Remember - the sensors in AF are checking the vertical and horizontal lines to focus (cross sensors at least, regular - only vertical lines)