I use my digital camera and set the settings to macro. This allows you to focus up to about an inch away from something. The macro setting on my camera has a flower for it's logo. Hope this helps.
A couple more basics are On macro the camera must be completely still. If you don't have a tripod brace it on a table or something. Don't use the flash. Play with different lightings for different coins.
I was using a nice camera don't remember exactly what it was. But this is how it turned out http://s462.photobucket.com/albums/qq348/TeukCoins/