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Message:: [QUOTE="-jeffB, post: 1770562, member: 27832"]52mm sounds like the front thread on an SLR lens. These tubes actually go between the lens and the camera body. Extension tubes shouldn't ever cause vignetting. The tubes are wider than the sensor and the back end of the lens assembly, so there's no way for them to get in the way of any rays passing from the lens to the sensor. When you put things on the front of the lens, they block the periphery of the lens' view, and that causes vignetting. Extension tubes will darken the image overall, as though you'd increased the f/ratio of the lens, and you'll have to compensate for that by taking longer exposures or using more light. There might be adequate macro-capable lenses out there for $180, but I think a set of tubes runs closer to $100, and it would let you use the best lens you currently own. (Unless, of course, that lens is a giant honking telephoto -- the longer a lens' focal length, the less effect adding extension tubes will have on it.)[/QUOTE]