Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Does it work with a Canon t3i?
Document: This works exactly as was described. It holds my Pentax K mount lenses on my Canon T3i tight and secure.
This adapter is high quality and allows my PK lenses to fit perfectly with no shake onto my Canon T3i (600D).
If you've never manually focused using live-view, you're in for a treat. Metering works without an issue, but aperture data is obviously not sent to the camera, so be sure your lens has external aperture control.Note: if you use a full-frame Canon camera body, Pentax lenses could damage the mirror. This review only applies to crop-cameras such as the T3i/600D.
Had several Pentax lenses and wanted to use them on new Canon T3i. Yes, it is possible with this adapter. The mechanism for opening the lens stop for viewing does not match up so view finder may be dim. (The adapter only mounts the lens on the camera body.) But hey, if you are too cheap to buy a new lens, you must put up with some inconvenience.Biggest problem was that the adapter was difficult to screw into camera body far enough to latch. Not much to grip the adapter with.
The adapter will work but not to good and when you mount the lens the position on the camera its not the same as in a pentax camera, I have the fotodiox adapter for Nikon Lenses on Canon Mount and I will buy the same brand for the pentax lenses..
I am so glad that I can now use my quality prime lenses, breathing new life into them!For those of you wanting to use your old PK lenses on full frame cameras, I have used and would recommend this adapter:Fotodiox Lens Mount Adapter with Dandelion AF Focus Confirmation Chip, Pentax K/PK to Canon EOS Camera adapter, fits Canon EOS 7D, 20D, 30D, 40D, 50D, 60D, Digital Rebel xt, xti, xs, xsi, t1i, t2i,t3, t3i,300D, 350D, 400D, 450D, 500D, 550D, 600D, 1100D,...
While this is a very well constructed adapter, it does not work with the Canon T1i. Even using the manual adjustment, I have found out that when you use this adapter you will over expose every shot. I don't know why but it does. I am going to try the adapter with the AF confirmation chip to see if this fixes the problem.
It fit my Canon like a glove, so it must have been made to high standards! I have not witnessed any problems with the release lever, it works as it should. I have not experienced any of the "wiggle" that others have with other adapters, and that's even using the giant 300mm prime lens that I have!RESULTSI was sad to find that this adapter did not work on my full frame camera, as the fotodiox AF confirm chip did. It kept giving me an error, and doing funny things with my mirror locking up.
After a couple of tries I gave up, not wanting to damage my camera. For crop DLSRs (specifically the Rebel t2i) I am pretty pleased with the results from this adapter. There is no light leakage, nor loss of quality. Infinity focus is solid, and after using this adapter with several lenses, I have not been disappointed. I have added a customer image (image of a duck) to show you the quality that this adapter will help you attain. Lenses are perfectly placed, and retain all the quality you would expect from the well made Pentax/For Pentax line!WHY 5 STARS?- Well made, no quality issues (+)- Not a bad price for the ability to use lenses that would cost upwards of $500 in the Canon line (+)- Does not work with full frame, and not because of lens problems (-)OVERALLI would highly recommend this adapter for those with crop sensor DSLRs.
This adaptor fits perfectly onto my t3i body and pentax lenses. The only thing I could recommend would be to purchase a separate adaptor ring for each lens you plan to use; as switching the adaptor between lenses is a bit tedious when in the field.Needless to say I'll be buying a few more :P
Answer: Yes