Hoya 52mm +10 Diopter 2-Element Close-Up Lens
A lens of 2-element, 2-group construction and a +10 diopter rating. Resolution is outstanding and focusing is possible at 10cm for super close-ups of insects, flowers and other small objects.
The magnification is about 1:2 with a 50mm standard lens (35mm camera), roughly equivalents to a 100mm telephoto lens. The lens should be stopped down as much as possible to get maximum depth-of-field.