Macro Photography with Extension Tubes
Look for a related post on using Close-Up Filters next month on Learning Digital Photography.
Want to get closer than close-up filter will allow? Stage II up the macro-focusing ladder is accomplished by adding an extension tube (or two) to your existing lens. Extension tubes provide the additional separation between your lens and imaging chip that’s required for close-up photography. You might think of it as an alternative to the more complex and expensive extension bellows that many camera manufacturers offer as a close-up accessory.
A typical extension tube set, such as Pro Optic’s includes three tubes of different lengths (31mm, 21mm and 13mm) that can be used in combination to obtain larger or smaller magnifications based on the total extension length. These tubes couple with your camera TTL metering mechanism and provide full auto focusing capability. A set of Pro Optic extension tubes cost less than $85, depending on lens mount.