[joeyc]

As many realize, the Sigma 24-70mm F2.8 EX Macro lens has an odd size filter (82mm) and a quirky lens cap. I like to keep the hood on my cameras as much as possible, even when stored in my bags. If you don't have a center pinch lens, this because a challenging feat, as well as potentially dangerous to the front glass as you fumble to try and get the cap to sit properly.

I just bought a 82-77mm step down ring, as well as a 77mm Sigma center pinch cap. This works out great - no vignette wide open - and spaces the cap away from the glass. In addition, I can keep the hood on at all times and use the same filters as on my 70-200mm.

Just a suggestion, take it for what it is worth. Here is a photo to demonstrate. And to note, the lens is terrific - best from F4.0, but quite usable wide open.

Joe

[little laker]

I was wondering if a filter adapter would cause vignetting.

Is yours the first version?
Mine is the second version, and looks a little different than yours. However it's also a SA mount, which might explain the differences.

[deejjjaaaa]

I was wondering if a filter adapter would cause vignetting.

it is a FF lens, so vignetting is less possible for APS-C camera

[pbo]

Huh? Is that the double-focus version? I had the double-focus version, from this angle looks same as yours. It had 77mm filter thread though... Really felt like a great lens - but misfocused on every FL except for 70mm - getting worse and worse towards the wide end - so I had to return it...

[joeyc]

I'm not sure what version it is. It is the latest non HSM version. Still listed on Sigma's page.

You engage manual focus by pushing the lens barrel towards you.