the main thing here is to get the coin being photographed parallel to the focal plane of the camera....photos of coins at angles often dont look right because the light falls away across the view. i use a macro table to take my coin photos, but a table and tripod do the same function, these allow the 90o view that is ideal. it doesnt matter if youre looking down onto the coin or straight at it, the view will be the same as long as you remain parallel to the camera. i prefer looking down onto a flat table as it gives me a constant, and once set up changing coins is easy. i always use aa a4 shet of paper for a background i try to use natural light as much as possible, but additional lighting reduces shadows caused by sideways lighting and for this i use a couple of simple anglepoise lights that use everyday 40w lights, raw allowing wb adjustments. natural light gives a nice light but is directional so some artificial light helps balance the image, for this reason its not always essential to use natural light, but preferable to control the light, as in studio work.........and its very easy to make a cheap coin studio.....table/tripod/balance lights. with photography, we find methods that work for us individually and 1 method is no more right than another, you have a good camera with a good macro facility and the ability to shoot raw, dont be put off by the extra work of converting a raw, the benefits of wb control and exposure are well known, but more importantly......while natural light is good, artificial light, once set up offers consistency and the ability to produce a batch of photos of a number of coins, without the problems associated with sunlight moving amongst the clouds/rain/snow.....whatever