This is probably familiar to a lot of guys here, but I didn't know it until early this morning, so hopefully someone else will benefit from my discovery to 
Don't ask why, but with the 10D powered on, I removed my 50mm prime from in, flipped it around, and held it "backwards" against the mounting, to find out how a "reversed through the lens" shot would look like.. Yeah I do silly things, ok?
But this was quite cool. The 50mm suddenly could focus 1inch from the subject, giving me macro-capabilities that where quite good
Of course, the f/1.4 at 1inch distance really make for some _SHALLOW_ DOF! Like 1mm maybe =D So "slower" lenses probably recommended (or heck, maybe a dedicated macro-lens while at it
) But I tried shooting a Norwegian coin, with it, and the result just blew me straight away =D Not the sharpest, and not the best color-accuracy. Probably lot to do with me "handholding" the lens in front of the camera. But I've now read some place that there's possible to buy rings with a bayonet-mount on one side, and filter-thread on the other, so you can attach it to the camera, and then attach your lens the opposite way by screwing it in by it's filter-threads.
Anyway, here's the shots. This technique looks like it could work in a pinch 
http://127001.org/div_pics/canon_forum/makro/![]()
These are 100% crops, and the coin is ~ 0.6 inches in diameter. Quite cool
Done with the 50mm f/1.4 USM, ISO-400 available light.


