Extension Tubes
Wednesday, July 15th, 2009 by Reed Hoffmann
For years I've struggled with whether to carry a macro (closeup) lens with me on trips. I love what I can do with one, but it's another piece of glass to carry. And if I'm not sure I'll need one, I often leave it behind. Now I've finally got a solution.
Macro (or micro) lenses have always been among my favorite lenses. If you want to shoot photos, but can’t find anything interesting, all you have to do is get closer. Much, much closer, to almost anything. You can always find neat pictures when you start magnifying stuff.
Getting started in photography in high school, I bought a set of closeup filters and had a lot of fun with them. In time I was able to afford the better quality and usefulness of a real closeup lens. As I’ve gotten older, though, I’m less willing to carry a heavy bag of gear, so sometimes the closeup lens gets left behind. And that created my dilemma. Then I remembered extension tubes, and finally bought a set.
Extension tubes are pretty basic – they go between the camera body and the lens and “extend” the distance between the sensor (or film) and lens elements. In doing that, they allow the lens to focus much closer than normal. They come in different lengths, the longer ones allowing even closer focus. Because there’s no glass in them they’re fairly light. And that also means they’re not very expensive. I bought a set of three by Kenko for under $200. I chose those, with 12mm, 20mm and 36mm tubes because they have the connections to allow my Nikon bodies and lenses to still communicate, so AF and auto-exposure still work. And, they can be stacked for even more magnification (which is what I did for this flower photo, stacking all three on my 70-300mm lens).
As good as they sound, they don’t replace traditional closeup lenses. when you put one on a lens it limits the focus to a very small range. In other words, you can ONLY focus close now. And, there’s some loss of light, so you have to compensate for that occasionally. Also, remember that when you get REALLY close on something, the depth of field can be almost non-existent. Be VERY careful with focus. The big plus is that they’re small and light, so it’s easy to keep one in the bag for those times you don’t have a closeup lens with you. And, they can be used with a macro/micro lens for unbelievably close focus.
So now the 20mm extension tube will have a regular spot in my camera bag. When I know I’m going to do serious closeup work I’ll bring my 60 or 105 Micro, but the rest of the time that tube will be there. You never know when a great closeup shot will present itself, and since I’m an old Boy Scout, I like to be prepared.
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