There are plenty of old vintage lenses you can slap onto your cameras, and Canon FD mounts are just one type. They might not be as good as other lenses (i.e. Nikon lenses), but for the hobbyist who can't afford several hundred dollars, you can find these FD's fairly cheap. After posting a few samples of my sexy 85mm F/1.2L Canon FD lens on a GH2, a few new questions came back around. I'll start by answering a few by saying, the FD lenses work better on MFT (Micro Four Thirds) cameras than on my Canon 5D Mark II full frame. By better I mean I can get a wider aperture, but if I stop down a bit to about F/2.0-2.2 with my 85mm, i'm getting excellent results.
These lenses have a completely different look, and that's not a bad thing at all. Lens flares, softness, and contrast are all things I personally desire. It's like slapping a Holga Toy Lens to a 5D Mark II - doesn't make a lot of sense, but it's pure creative fun for the artist. There's some other fun facts about old FD lenses, and Caleb Pike over at DSLRShooter.com put together the best video with sample footage you'll find online. You'll get an idea of crop factor, usable aperture, and yadda yadda yadda. He's using basically the same adapter i'm using with the Glass Element. If you haven't seen it before, it's an oldie but goodie. If you've got further questions, you can hit him up over at Vimeo here: http://vimeo.com/17805517 [Thanks Caleb]
You can check out the video sample I shot with GH2 + Canon 85mm FD here: http://cheesycam.com/canon-fd-lens-85mm-f1-2-on-gh2/