Max filter thickness Sigma 10-20 can handle without vignetting

All,

Can anyone advise what's the maximum thickness this lens is able to handle at 10mm side without causing vigneting?....since I see there are 2mm, 3mm, 5mm and 7mm filters out there.

Any sharing?

The coking-P wideangle filter with the one slot didn't cause nay visible vignetting at 10mm when the filter was oriented properly. I don't use the screw-in filters.
--

http://www.pentaxphotogallery.com/home#section=ARTIST&subSection=2323984&subSubSection=0&language=EN

K10D, K-7
Pentax Primes: DA21/3.2, FA*24/2, F28/2.8, FA43/1.9, FA77/1.8, F135/2.8
Sigma Zooms: Sigma 10-20, Sigma 100-300 F4

'Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming... 'Wow! What a ride!'

I use a Tiffen 72mm diam. screw mounted CP that is 7mm thick without vignetting at 10mm focal lenght
--
Richard

The diameter of my CP is 77mm, not 72mm as stated in my reply...sorry
--
Richard

Finally received my Kenko 77mm UV filter and CPL filter.

They have pretty thick filter ring; 7mm, it doesn't cause any vignetting to my Sigma 10-20 EX DC at widest aperture and FOV.

Got them from this ebayer.... http://photography.shop.ebay.com/Lenses-Filters-/78997/i.html?_catref=1&_fln=1&_ipg=&_ssn=jiahaochukoudianzi&_trksid=p3911.c0.m282

Also tried to stacked both the filters to see if it vignets. Yes, at 14mm, it's beyond Sigma 1020 tolerance. You get severe Halo.

I have used a Hoya Super Pro 1 CPL on my sigma 10-20 at 10mm with no discernable problems, as I see it this filter is 5mm thick.

Mike

Tested the CPL which is 8mm thick on my Sigma 1020. No vignetting too.