Quote Originally Posted by Cage View Post
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Did you get any vignetting with your set-up? And my neighbour is an engineer so the mod to bring the holder width back to 150mm should be a breeze.

Cheers
The filter holder had to be slid onto the lens(built in hood type) to a specific point close enough to the front element so that it didn't vignette, but not close enough so that the filter(inside face) didn't rub on the lens' hood.

I have a plan to add a dollop of epoxy onto the filter holder to act as the stop point for the holder so it was quicker and easier to slide it on without the need to finesse where to fit it(at the right spot).

Can't remember exactly if it gets mechanical vignetting at 12mm with a lot of rotation of the holder but as the entire holder needs to be rotated and not having hard stops for the holder to rest on the front of the lensit's hard to quantify properly.
Because I use only grad filters you would get vignetting of course as the lens and filter at the extreme corners had the light coming in at extreme angles. But mounted carefully I could set it so that I got no mechanical vignetting.

With the lens orientated at 90°, ie. portrait orientation .. it was a lot harder to get any vignetting at all.

Not long after the new Sigma 12-24/4 came out I basically decided to get one ASAP! seems a very good update from the old one I have.
Problem is finding the time to do any photography at all .. so it's all taken a bit of a back seat.
When I get more time to get back into it all again(soon! ) all this hacking about with the holder for the old Sigma will be redundant in the end as I'll definitely get myself the f/4 lens to play with(as I already have the filter holder for it).

Did have the time(more accurately I MADE the time) a few months back to get out for a bit of a wander and my last effort with the above lens and holder was this image:


Note the very slight vignette at the top LH corner. That was my stuff up.
I took lots of time to setup camera/lens, zoomed to 14mm for framing(some clutter on the left and a half a tree on the right, I zoomed out of the composition) setup the filter holder just right, switched to liveview adjusted the filter a little vertically but that adjustment knocked the holder out of whack a mm or so and I got that small vignette in the corner as a result. Only saw it at home on the PC later. Thought about cloning or cropping it out but I'm too lazy for that kind of editing malarkey!
Serves as a reminder for next time I'm out there!.

The mod to get the filter holder width to 150mm is easy.
The harder part is a half decent mod to make the stoppers so that the holder sits squarely on the lens .. which is the really hard part to setup .. and also to sit as close to the front element without having the filter touch the lens or element(ie. scratching).