Extension tubes

If your camera takes interchangeable lenses, you may want to use extension tubes rather than close up attachments. An extension tube fits between the camera body and the prime lens, moving the lens farther from the sensor so that it can focus closer. Since a tube introduces no additional glass elements into the light path, it usually furnishes sharper results. However, offsetting this advantage is the bother of removing the lens, fitting the tube to the body and then replacing the lens.

Like close up attachments, extension tubes are not very expensive. They usually come in sets of three or four, each tube having its own length. By combining the tubes in various ways, as well as using them singly, several different extensions may be obtained. Each extension works within a limited range of distances, just as with close up lenses, but the scope of the entire set covers images from about one tenth to full life size.

You have a choice between simple manual tubes and the more convenient automatic ones. Since there is only a slight difference in price, the automatic tubes are recommended because they let you retain all the automatic exposure functions of your lens. If your camera lacks through the lens metering, figuring the extra exposure needed with a tube in place can be a chore. Instruction sheets provided with sets of tubes sometimes give exposure increase factors along with lens to subject distances and fields of view for each combination. If not, experiment, bracket your exposures, and keep notes for future references.


More about close up lenses

- Supplementary close up lenses
- bellow lenses
- macro lenses
- hints for close up photography
- tips for using close up magnification