I was testing a new method of photographing coins and chose as my test subjects my favorite cat coins.
So I thought I would share them here, for no reason at all :)
I used wireless flash pointed from the side slightly higher than the level of the coin, used a piece of white paper to scatter the light and a black screen on the other side. Since I used the camera flash to drive the external flash, I had to use another screen to block the camera flash. Basically a variation of what many tutorials advise.
iso100, f/11, 1/160. Flash at 1/4 power, optimal distance and angle had to be found by some experimentation.
I do not own a good macro lens, so used a sharp 24mm lens, because it has a nice minimal focus distance, and then had to crop a lot. But still enough to get at least 700 by 700 pixels even for smaller coins. And used postprocessing in photoshop, mostly two things -- using levels to spread the histogram and modify brightness/contrast.
I'd be glad to explain in more details, but I am still new to this method myself, I used to simply use macro mode on my old point and shoot camera before.