Mark1948

I love my Sigma 8-16mm but I also love CPL filters & therein lies my problem. In order to build a lens that wide, the front element bulges outward a good .66" beyond what otherwise would be the front of the lens. Sigma also provides a built-in lens shade to both protect & shade the front element. That configuration leaves nothing to which one can attach a lens cap or filter. In order to accommodate a lens cap, Sigma provides a 1" ring that slips over the outside of the lens shade. That 1 inch ring is threaded so as to accommodates a lens cap or a 72 mm filter.

The problem, as you astute readers have no doubt already realized is that vignetting with the 1" ring in place is so severe as to compromise the use of anything, including any filter mounted on the ring. My thoughts have turned to engineering nightmares & unworkable solutions that would make Rube Goldberg blush so, as hope springs eternal, I'm hoping someone has a better idea. Any/all suggestions appreciated.

Bill_de Loc: US

Maybe this:

http://www.adorama.com/fdfa66csm816.html?gclid=CMLGloLeldECFdGIswodFLMJpQ

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twowindsbear

I believe you'll find that len's angle of view to be so wide that a CPL would give such uneven effect as to be more trouble than useful.

IMHO & YMMV - of course.

Mark1948

Wow! That was fast & looks like it's made for the task. Thanks Bill

Bill_de Loc: US

No problem. Google is a wonderful tool.

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speters Loc: Grangeville/Idaho

Check out the wonder-pana from FotoDiox, I think their fixture fit this lens, so you could use any filter on it!

BHC Loc: Strawberry Valley, JF, USA

This may also allow the mounting of Cokin/Lee/Singh square filters......

DOOK Loc: Maclean, Australia

Have you looked in to using a CPL on an ultra wide lens? If CPLs are used on lenses wider than about 35mm, sky banding will be very noticeable. On an 8-16, it would be really bad.

davidrb Loc: Half way there on the 45th Parallel

Mark, you will have to bite the bullet and use the features of PP for filters. The Canon 11-24mm and the Zeiss 15mm both fall into the same category. Third party bolt-ons may or may not work well but they are hassles with which to work. The Zeiss has a CPL but at 95mm it has troubles getting such a huge expanse evenly filtered. The Canon will accept a rear polarizor gel so I can work around water with it but sky shots are done solely in post-processing. You are working in an area where information is not readily available so you are sort of on your own. Are you really surprised that the 1" ring leads to "vignetting"? Possibly looking to other users of this lens may get you some useful information. God luck in your search.

amfoto1 Loc: San Jose, Calif. USA

This is correct and will be an important consideration, using a C-Pol on such an extremely wide lens. Here's an example showing how uneven the effect can be (20mm lens on full frame, so equiv. to about 12 or 13mm on APS-C... wide, but nowhere near as wide as your lens!)....



In the above image, the afternoon sun was off to the left. A polarizing filter's effect is strongest 90 degrees from the light source, and tapers off to almost nothing toward 180 degrees either way. The wider the lens, the more this "issue" will shot up. For the above shot, the clear blue sky was kinda boring, so I used the C-Pol deliberately to emphasize the white lighthouse. But in a lot of other situations it can be a "problem".

Here's another shot done with the same lens and polarizing filter, but this time with the sun overhead and slightly behind me, more "perfectly positioned" for the filter so the blue of the sky is more even toned throughout...



It also helped that for the shot of the Morro Bay harbor I was using the lens on an APS-C camera (where it behaves like a modestly wide 32mm would on full frame).