For example, this rig looks impressive:
The biggest problem with an iPhone is motion. You can solve that with a few books and a rubber band:
You can even get more magnification with another rubber band and a loupe:
Taken through a loupe with LEDs
A higher powered loupe could certainly do better if you can get light in or aren't bothered by LED lighting. Lighting does become more of a problem with the loupe because you have to be so much closer. I used the LED lights on my loupe for the picture above.
The LED's do affect color, though, so is there any other way around that? There may be: this Cortex Camera app is supposed to help with both low light and motion blur.
How does it do that? By taking multiple exposures and processing them into one. This explains in more detail.
Does it work? Well, I'm not really sure. I've tried it in side by side comparisons and I can't see much difference - can you?
iPhone Camera Flash on
iPhone Camera Flash off
For my needs, I'd rather be higher up with no loupe and use the iPhone zoom to get the magnification. It's not quite as sharp, of course.
Note: All my coins are in a safe deposit box. I keep nothing in my home.
Contests and giveaways: http://coins.aplawrence.com/2014/05/contests-and-giveaways.html