I've tried different lighting, angles and cameras. I've read the advice of the experienced photographers on this website. I don't have a lot to work with here, but I finally found a way to take what I consider respectable pictures of slabbed coins. No big dollar items here, and the pictures are mostly for internet sale and auction sites. Dealing with the reflections was the biggest challenge for me. My USB microscope has LED lights. I can turn them off and use side lighting but I don't like the coloring of anything I tried on silver coins. So I use a block, just small enough to tilt the reflection of the lamps out of the way. Granted, I lose some clarity either at the top or the bottom of the coin when tilting it, but I'm okay with the trade-off.
Mine does not, but I can make adjustments like that in the photo-editing software after I take a picture.
I try, try, try not to use any of the editing features (except crop), but sometimes I just need to tweak the white balance of the shot. I avoid the sharpening function too, I agree it just usually makes things sharper, but grainier. If its a blurry shot I'll usually just reshoot.
What kind of phone? Mine has in its settings, ISO, white balance and brightness/darkness settings. Try 3 lamps. 2 up high at 10 and 2, and one almost at coin level at 6. You can also hang a piece of oven paper in front of the lights to control glare, experiment with the distances. These are shot through the plastic capsules
