Sigma 10-20mm Problem? - DPChallenge Forums

Tamron AF 18-200mm f/3.5-6.3 XR Di II for Canon

01/03/2007 10:34:12 AM · #1

I just received the Sigma 10-20mm lens and took a few quick shots indoors yesterday. The first thing I noticed that the focus ring will keep rotating and rotating. There is very little resistance when you get to minimum or maximum focus and it's easy to go beyond. To me this seems like a defect. Or is this typical of this type of lens?

Also, there seems to be a lot of vignetting at 10mm, but it was quick shots indoors with the flash. I suspect that the built in flash doesn't have that wide of coverage. I'll take some outdoor shots today at lunch to verify.

UNTITLED

Canon EOS-20D

01/03/2007 10:46:03 AM · #2

The rotating is normal, I think it is a product of the manual focus override when in autofocus mode.

I've had no problems with vignetting on mine, even with a polarizer on the lens.

Tamron AF 18-200mm f/3.5-6.3 XR Di II for Canon

01/03/2007 10:53:10 AM · #3

I wondered if it could be due to that as you state. My concern is that accidentally rotating too far would damage the lens. The AF seems to work fine. I may give Sigma a call anyway to verify this. Thanks.

UNTITLED

Canon EOS-20D

01/03/2007 11:07:38 AM · #4

I've never given it a second thought, but I would be curious to hear what they have to say.

Also wanted to add about the polarizer, since I mentioned it, that I don't use it much now. It does some really funky things to the sky because of extreme wide angle and the filter being dependent upon the angle in relation to the sun. I've only had success with the polarizer on rare occasions.

tate

Apple iPhone 15 Pro

Nikon AF Nikkor 50mm f/1.4D

01/03/2007 11:28:41 AM · #5

Is it a low profile (thin) filter? I learned this a few weeks ago in a thread - if the filter is too far from the glass you might run into issues.

Message edited by author 2007-01-03 11:29:26.

Canon RF 24-70mm f/2.8 L IS

01/03/2007 11:30:49 AM · #6

I have a thin polarizer for it, but haven't tried it yet. I need to do it soon because if I don't like it I'll return it while I still can.

kirbic

Canon EOS R5

01/03/2007 11:53:10 AM · #7

The focus ring behavior sounds exactly like that on Canon USM lenses with full-time maual focus, and I'd bet that's what it is.
With regard to polarizers, yes, only part of the sky will be darkened to maximum degree, specifically that part that's close to 90Â° from the sun. When using a polarizer with a lens this wide, you need to be careful of what direction you're shooting, and how much/what parts of the sky you include.