This will allow you to mount up a regular 50mm and go from 1/10ths life size to 1:1 life size (more than that if you focus the lens closer than infinity). Glass is not perfect, but in sample images, the slightly reduced (from what I assume to be normal) contrast was the only thing affected, sharpness was still good for what this does. The focus control is sometimes hesitant to move, and the cosmetics are not perfect either, so I've priced accordingly. I do not have caps for this item, can provide sample images upon request. $20 shipped in CONUS, $20+shipping worldwide.