Opinions Please

I'm not an expert yet , but I have been having some good results lately so I will give an input anyone can step on if they wish....I think the first thing I realized is LIGHTING LIGHTING LIGHTING...is a very key factor...as you know I'm sure..however..there is a great difference on how to approach a particular coin and I SHOULD SAY the type of metal..copper VS silver for example are at extreme differences in there requirements...
My first impression is you have too much light...
But that's not actually correct....
The cameras 3 main setting points interpret what they think they see and you get (your picture)what it thinks is best for you...
Those 3 things are,, ISO shutter speed and the F stop value ....only lately have I actually seen on screen seen the actual differences in the settings before taking pictures using the cameras live view funtion, which not all cameras have..however.. its the knowledge of these settings and which way you tweak them, and what the outcome will be... For example...I used to think I needed the lower
F stop and higher shutter speed on shiny coins..I was trying to hit or fix the shutter at say 800 to say 1500
out come was ok on shiny UNC coins...
Practical application reveals I needed lower shutter speeds
however,, After a week of playing..I then dropped the speed to around 650 or so.... there is a point as you lessen the shutter speed say to 500 then to 300 WITH my present settings, the coin was to overlit and had the washed out look as your coins do...when I lowered or slowed my shutter speed down...TO much light..
Most cameras control the shutter speed do to the aperture setting you may choose, it allows more or less light on the coin.
depending on the type of coin you are shooting...there is a balance ....Having full manual control over the camera is a must or it takes a bazillion guess shots to get one good one....I leave all my settings as is and change one feature at a time to review the results to see if I am going in the right direction.....I don't think its the lights your using right now but rather how your settings are at the moment...
are using the light source...Dave and Ray could give you some better general reference starters , say ISO and F stop For copper and old nickles settings by which you can slowly alter.. If your using a point an shoot camera,, try the white balance and reduce the light settings and see your results...hope this helps...

I'm not fond of having the primary light shining from below as you show in these photos. It's an unnatural perspective. The most obvious outcome that illustrates this is the light shining on the Buffalo's belly. The only situation I can think of where this would occur is if the buffalo was a statue, and it was night time with lights shining on it from below. The other example is the illuminated cheekbones of the Squaw and Chief, which again seem very unnatural. Most folks will recommend lighting from high clock angles, and although they may not really know why, this is the reason.

Have to use indirect light. I usually set my iso at about 400 with f 11. Have two systems. I built a white box, white all sides with front open to position camera, cut two holes on either side of box and shine light in from both to the back of box. Put coin or anything small I am shooting in box with no light shining directly on subject. Then use another light source I adjust hand held most of the time aimed at the top of the box. Camera is always on tripod.
The other I am now playing around with is setting the camera to shot straight down with a piece of glass set at a 45 so the camera has to shot through the glass to take the picture. I set up a very bright light shinng at the glass directly at the coin, positioned under the glass with a small object in front of the coin to block direct light. Idea is the light reflects off the glass and on to the coin. When done right the pictures are fantastic. So invision a camera at the 9 oclock position the coin at the center of the dial and the light source at the 3. With a small dark object between the center and 3 to block direct light on the coin. The glass would be at a 45 going from outside the 9 to just over the box. Hope that makes sense. If you have a good camera, shot in RAW mode and then you can adjust a little in photoshop or another program that accepts RAW files.