If you want to get closer to your subjects for increased magnification, the standard route is to employ a macro lens when shooting. However, if you only have occasional use for a macro lens it may seem like an undue expense. If this is the case, then it’s worth having a look at Canon’s EF12 II and EF25 II Extension tubes. These can be used with Canon’s EF-S lenses as well as most EF lenses. They fit between the lens and camera body (just like an Extender) but instead of having optics, they are simply hollow tubes. They effectively move the lens farther away from the camera body’s sensor (or film plane), thus allowing you to focus on subjects much closer than the normal minimum focusing distance of the lens – they thereby achieve increased magnification. It’s not true macro, but for large insects like butterflies and dragonflies, or for shooting flowers, it’s a very good solution.
Source: Canon Professional Services
Contributed by: Martin J. Allred