I'm guessing you'll always get a glare from slabs if you use this, and if you don't, you'll get really flat looking pictures. Pretty cheap to try it, though.
Everything I learned about coin photography, I learned from @messydesk and a great CD he made giving pointers. While I am very much a novice, I know that direct light tends to cause glare. I would personally not use this and recommend spending $25 or so for 2x Gooseneck lamps that use CFL bulbs.
I know absolutely nothing about smart phones. I still use the old star track flip phone. But one thing I do no about LED lights have a tendency to give off a bluish purple glare I have seen quite a few very good photos that members have taken with their smart phones. Maybe someone with enough knowledge in the smart phones will start a thread concerning coin photography. Since I find a lot a new members are using their smart phones to take photos of their coins. And just like USB cameras every year there coming out with new accessories to improve photo taking with your phone. Lighting is always going to be a major issue when it comes to coin photography. USMC60
While I agree that offset lighting is the best method, how many people do you think would carry them around with them? Chris
Good point, I guess I had only considered this question based on an "at home" setup vs one for on the go.
If I could modify this light, I'd make it a ring in 3 segments, each of which could be controlled individually (on/off/brightness). Bare LEDs would be covered with a daylight-corrected diffusion filter. I'd then put each segment on an extendable arm so that they could be positioned away from the camera by a few inches. For bonus points, the whole assembly could be rotated in place by up to 60° so that I could easily adjust 10-and-2 lighting to be 11 and 3, 12 and 4, 9 and 1, etc. Then I think it would be pretty useful on the go. It would set you back more than $9, though.