(I wrote these two paras before you posted the last two ..)
OK, well, the best thing to do is to experiment with your camera until you have found and played with all the settings. The exposure compensation
comes under "Creative Performance Controls" so there may be a setting that activates those options. But that's more advanced. If you are new at this, then maybe start with the simple stuff: getting the right lighting and focus, getting a setup that holds the camera steady and the coin in the right position.
Take the largest and most detailed picture size that your camera can take. If you need to reduce it to upload here, use some image manipulation
software. Did you get some with your camera? Picasa is a free download from
Google and is supposed to be pretty
good, though I don't have personal experience. The principle is to start with as much information as you can get, and reduce it when necessary - you can always to that, but there's no way to increase it if you start with a low resolution pic.
(onwards ...)
So you are already doing some of that -
good. Your coin really is that grainy, I am afraid; the camera magnifies all its faults, as I know to my horror. Those last shots are really pretty
good. Now I want that coin myself ... an effect your earlier postings did not produce! The image is a
bit yellow in tone, probably the effect of your light source; either adjust your white balance or adjust the tone with
software.