Definitions for "Extension tubes"
Tubes made from metal and, more frequently, plastic inserted between the lens and the camera, thereby making the lens to film distance greater. The result is increased magnification for close-up photography.
A set of rings or tubes of varying lengths, used between the camera body and lens to permit focusing the lens on subjects at close range.
These are a handy way to turn any long lens into a macro lens for ultra-close shooting. They are hollow metal tubes that are mounted between the camera and the lens. Typically they come in a set of different lengths which can be combined. It is a good idea to open up the lens a little when using an extension tube, as a little light is lost. It should be noted that they do not work when used with wide lenses. [Go to source