# Are "slim" filters needed on 17-40 or 24-105 for full frame?



## Scarpz13 (Dec 25, 2012)

First off, Merry Christmas & Happy Holidays to you and yours 

I was fortunate to move up to full frame this holiday season; and I thought I had read somewhere that regular UV filters can cause vignetting on the wide end for the 17-40 & 24-105 on full frames.
I have always had B+W 77mm UV Haze MRC 010M Filter on these two lenses... I have been testing them out on my new 5Diii (hooray), but can't seem to notice any significant vignetting at all... just a few indoor test shots, but nothing that I can notice. 

Should I be changing these for the "slim" versions? I'd rather not due to additional expense, and lens-cap attachment issues with slim filters...

thanks, as always for your help.


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## neuroanatomist (Dec 25, 2012)

No problem on the 24-105mm, probably none on the 17-40 (haven't tested, but the 16-35 II is ok with an F-Pro. 

Here are my results from the 24-105L:




Filters and Vignetting - EF 24-105mm f/4L IS by Dr_Brain, on Flickr


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## CharlieB (Dec 25, 2012)

For one filter - no

For multiple filters - yes

FWIW, I'm using a regular thickness HOYA HMC on my 16-35/2.8II - no issues at all on FF at 16mm.... however, on some filters you're gonna have to make sure that the mounting of the filter itself in the ring prohibits the filter from hitting the front element. A flat - and cleanly cut - piece of notebook paper is about .004 to .006 thick (not much!) and should slide between the front element and the filter when trapped between them.

On your two lenses, I don't think you'll have any glass-to-glass problems at all.


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## Scarpz13 (Dec 26, 2012)

Thank you both! I should have known you would have conducted a sophisticated test like that, Neuro. Appreciate you sharing your results...

If I may ask a follow up question; I noticed you tested two filters stacked together; why would you do that? Do you happen to stack your CP filters on top of your UV filters? I like to keep my UV filters on at all times, but also thought putting a CP over a UV had negative effects on picture quality as well.

Cheers!


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## neuroanatomist (Dec 26, 2012)

I generally remove the UV before mounting another filter, but sometimes I'm in a hurry to get a shot and I stack them. Also, I sometimes want to stack a CPL on top of an ND filter.


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