Filter glass?

I have a Tiffen 77mm filter glass for "protection" on my 10-22mm Canon lens because I shoot skating and don't want it to get hit, but I'm curious as to whether or not the glass on the filter is the same quality of my Canon lens and if it isn't is it hendering my photo's quality?

i'm wondering the same thing

The definitive answer is: Maybe.

is yours a wide angle (thin, no front thread) or regular tiffen 77mm? if regular, it may cause vignetting when shooting at the wide end.

i don't believe tiffen glass UV filters are mulitcoated. they can degrade your image by causing flare or ghosting, especially when shooting into a strong light source.

why not do a simple test shooting the same scene with and without your filter? you might want to pick a scene where the sun (or a light source) is just outside of your view and then check the resulting image and compare for flares.

my quick answer is to either not use a filter, or use one that is multi-coated and is designed for wide angle lens (thin). B+W MRC, Hoya Multicoated and Heliopan are the usually recommended.

-alex

I don't think most filters will stop a slap shot, (if you are shooting hockey) but if you buy a filter buy the best you can afford. 77 mm is a very common size so you can use it on many lenses, especially Ls.

Canon filters are rebranded Tiffen - which by and large, stink.