You can adjust the camera mount's height a pratty good bit. When I first tried it I couldn't get close enough to the coin to get a good pic. Then I realized I could slide the mount completely off the riser, flip it over & put it back on. In that position I can get the camera right on top of the coin.
It's a pretty interesting piece of equipment. I'm pretty sure it was intended to be used for making copies of photos & documents. The flat piece on the base flips over & has a different size grid pattern. There is a small placard that references a chart that tells how high to set the camera mount in relation to the size of the document/photo being copied. There was some other pretty neat stuff in that shed.