Thanks a lot for these replies..I didn't have to wait long.
I never even considered sunstars. It's something I actually like to include in an evening photo sometimes. So what you're saying is that , for sunstars , the 3.5 is better.
Also the advice regarding testing is really helpful. I'll do this when I get the lens.
& yes, I found the 82mm filter prices are significantly higher than the 77 in the UK.
It's
really useful to know this stuff before buying.
Regarding the sharpness difference I get the idea that ,
in practice , there's no difference worth considering - sample (& photographer!) variation being a bigger factor - probably(!).
So , thanks again. I hope to be able to offer advice to others once I've put all this into practice.
NB I already have a Nikon D7000 plus a couple of lenses & decided to invest in a K5 system as well. I'll post something soon about why! It may be helpful to anyone making this choice whilst they're still current.
Last edited by sdgreen; 06-11-2012 at 09:19 AM.
Reason: Addition