autofocus seems out of whack with polarizing lens

[NancyM]

HI All,
I have the Tamron 70-200 2.8 lens and I love it. I used it yesterday with a new polarizing lens. Will this throw my autofocus off? I was taking photos in the evening - the golden glow of the sun was still there and my lens was zoomed in all the way to 200 with a 2.8 aperture. My focus was terrible!!

Does the polarizing lens change the ability of my lens to focus? (Please excuse, I am an enthusiastic hobbyist and I want to take great photos. I just have a lot to learn.)
Thanks!
Nancy

[Skoropada]

Is your polarizing filter a Circular Polarizer?

Other types of polarizing filters get in the way of the camera's autofocus system.

[DanielLane]

the polarizer should not hamper the auto focus at all. My guess is that your camera was trying to focus on something that wasn't quite clear in the first place. Like a soft cloud or something. What particularly did you have it focusing on? What focus mode was it in as well? SIngle point or no?

And besides, drop the polarizer for the sunset. Use a neutral density or better yet, a split neutral density for sunsets. you will like the results.

[NancyM]

Thanks so much for your response!
It is a circular polarizing filter - made by Bower. It was around $60 - not very expensive. I only know it is circular because it says so but now I am wondering if that means there are two rings around the filter that both spin.

Do you need a lot more light when you are shooting with one?

[Skoropada]

Originally Posted by NancyM

Thanks so much for your response!
It is a circular polarizing filter - made by Bower. It was around $60 - not very expensive. I only know it is circular because it says so but now I am wondering if that means there are two rings around the filter that both spin.

Do you need a lot more light when you are shooting with one?

Here you have more information about polarizing filters.

Polarizing filter (photography) - Wikipedia, the free encyclopedia

[NancyM]

I was focusing on a heron but it was pretty far away. (darn things are either too close like my pond or way across the lake.) Maybe it was too far to focus on.

My focus point was correct but I did just notice that my focus is set for single servo AF and the AF area mode is dynamic. i don't remember having dynamic set before. I guess I better check that out.

Believe it or not, I did check out the Wikepedia article before I posted the question. It didn't give much specifically about focus.

I took photos in Times Square at night with it on and the focus was pretty sharp.

[Hill Country Hack]

What was your shutter speed? Were you using a tripod? Your issue may be camera shake if not on a tripod. One should have a 1:1 ratio of shutter speed to focal length. You said you were out all the way to 200mm, so if hand holding, your shutter should be at least 1/200. I have greatly decreased my camera shake by using this formula.

I have not had any issues with a polarizer jacking up the focus. I do that all by myself thank you very much.

[NancyM]

It didn't seem that slow when I metered but it was 1/160. Shooting with a subject that far away, it wouldn't take much shake to cause a big blur.

okay...i will give the filter another try. I was worried about my lens and my camera.
Thanks, everyone for your help!!