Would It Be Feasible...?

[Willamette]

I've had several point & shoots - all Canon - and upgraded to a T3i and 18-135mm lens several months ago. The other day I was going through my parents' attic and found my uncle's 35mm Pentax P3. There was something wrong with the body but the lens (50mm f/2 A) is in good condition. A nifty fifty is on my wish list but I don't have the cash to drop on a Canon lens... So, my question is, would it be feasible to buy an adapter that would allow me to put the Pentax's KA mount lens on my T3i's EF mount? I realize that the lens will not auto focus, but that's fine with me.

 

[Big Mike]

Welcome to the forum.

This question (or a reasonable facsimile thereof) has been asked several times in the last couple weeks...and many more before that.
In a nutshell, unless you have a pretty decent lens to start with, it's usually not worth the hassle.

The main thing to know is that there are two types of adapters, with lens and without. If you get one without a lens, you loose infinity focus but don't hurt the image quality. If you get one with a lens, you can focus to infinity, but your image quality is subject to the quality of the lens in the adapter (usually pretty bad).
And of course, on top of that you don't have auto focus or auto aperture control/metering.