Trying To Get The Perfect Coin Photo -- Will Full Frame Help Improve?

I'm sure others will have opinions as well, but I don't believe switching to a full frame camera will help you out. If you haven't already done so, I'd try changing the camera settings and lighting first.

Color issues are typically related to white balance and lighting. Have you tried a manual white balance setting using an 18% gray card?

F4 also seems a bit low to me. Most lenses are optimized around the F6.3-F8 range. Closing the aperture to this range may help with your edge blur.

The only thing I know that you can do to reduce reflections is to eliminate the source of the reflections. Try to make everything in your setup black so that extraneous light is being absorbed instead of being reflected to the lens.

Also, if your purpose is to view the photos on a computer monitor, then you have to keep in mind that the quality and settings of the monitor play a big role in what you see as well.

Having said this, to my eyes those photos look pretty good to me on my monitor. Might be a bit out of focus (top to bottom on the obv and left to right on the rev) or it might just be me. If you haven't tried manual focus then you might want to give that a try as well. I've found that with my Pentax camera in autofocus that things aren't always quite in focus (even though autofocus is telling me they are) and I sometimes have to switch to manual focus. This could also be because your depth of field is more limited at F4.

Looks good to me

Treasureman,

My Pentax camera doesn't have live view or tethering capability, but just about everyone who uses a Canon camera swears by the tethering capability. If you have a laptop, or can get your setup close enough to a desktop, computer then it's probably something you should try.

Is the LED lamp a linear source or a point source? Point source is better and the typical advice is to use 2 of them at the 10 and 2 o'clock positions, but you really just have to experiment with lighting and it will vary with different coins. The temperature isn't that critical as you compensate for that with white balance and 5000k is just fine. When you use multiple lights then they should be the same temperature for the best white balance.

Are you using a copy stand or a tripod for your shots? Either can work (personally I use a homemade wooden copy stand), but you want to be sure that the coin is parallel to the camera's sensor. A decent bubble level can help you out with that.

To diffuse the lights you'll need to put a translucent material between the light and the coin. How you do that will depend on your lights, but there are generally two methods. Put the material directly over the light or put the material between the light and the coin and shine the light through it. Folks have tried various things for the translucent material including milk jugs, ping pong balls, Canson Opalux sheets, tissue paper (watch the heat of lights!), muslin cloth, etc. Quite a few folks use the Opalux cut and shaped in various fashions.

I agree with Ray (rmpsrpms) that a black background is better than a white background. Personally, I use an 18% gray card background as that lets me easily adjust white balance in post processing of the RAW file. You didn't say whether you're shooting in JPG or RAW format. There are advantages and disadvantages to both and I'd recommend you try both to see which you prefer.

Ray's been at this a long time and has given many of us (including myself) very valuable advice. I highly recommend trying anything he suggests.

Treasureman...your adjustable color light sounds interesting. If you can adjust it to 3200K, you can use the tungsten white balance setting.

Are you hand-holding the camera? If so you will get the biggest benefit from a copy stand. This will hold the camera steady and flat vs the coin.

Yeah, for the same reason APS-C is better for coins than FF, M4/3 is better than APS-C...lower magnification. You can also mount pretty much any lens to a M4/3 camera, so they can be a great choice for coins.

There are folks who swear by the Oly focus stacking capability. Only drawback I see is it's limited to the max magnification of the native macro lens. I've heard of some folks using microscope objectives in front of the lens to do higher magnifications, but am not sure how successful they've been. Certainly for walkaround macro, or perhaps shooting ancients with deep relief, the in-camera stacking method would be useful.