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Lens Extension Tubes for Macro Photography


Macro Photography extension tubes



Achieving high close-up magnification

As we already wrote about in a page devoted to the reverse lens approach in macro photography, unless you have a real macro lens at hand, you’ll get the best macro pictures by flipping your standard lens and, in order to focus in on a very close object (thus achieving high magnification factors) you’ll have to place your lens at a considerable distance from the sensor.
A lens extension tube is standard macro photography device which is to be placed between camera body and the lens. It is in a nutshell just a tube, without any optical device (read: lens) inside. Its function is just to move the lens away from the camera’s sensor.
While it is not an essential tool for the photographers bag (a tripod is, instead), consider extension tubes as great add-on for macro shooters.
Please note that, when in use, extension tubes prevent the lens from focusing to infinity. This should not be a problem of course, as you are shooting very nearby subjects. Remove the tube, and all will be back as normal.

Pros of extension tubes

Extension tubes are lightweight and easy to use: just place them between camera and lens, and you are ready to go.
An example of extension tube is Kenko Uniplus Tube.
Most tubes come in 3 sizes and, by simply stacking them in various combinations, you can obtain a lot of different magnification degrees.
Also, you can craft an extension tube by yourself, which allows you to shoot macro at almost no extra cost.

No matter how you manage to place your lens at some distance from the sensor, as long as the whole system is properly focused and sufficiently stable, you’ll get the images you want.1
Here is a couple of small selection ofthem:




Cons of extension tubes

All that glitters is not gold, and so is for extension tubes as well.
First of all, they do take space: inside a photo bag they take about the same space as an average zoom lens. As such, it might be annoying at times.

Also, they cost money: unless you craft one by yourself, you have to pay for them. In which case we suggest you do not by the cheapest on the market, as they tend to be unreliable. We have reviewed a few of them which are good enough to suggest: you can safely buy them online at amazon.com and have them delivered in a few days.

Extension tubes do have another drawback: they are fixed lenght. Ok, you can stack them, but still you cannot choose the exact magnification ratio. Macro bellows are, in this respect, much more flexible tools, in that they allow you to accurately set the distance you want, and thus the exact magnification ratio. Macro bellows are, though, much more expensive and fragile.

Last, but not least: most often tubes (and bellows alike) require some bellows factor exposure compensation. Even if all the camera settings are properly transmitted through the tubes and calculation is not required, still exposure should often be increased, and this might adversely affect some shots. It is the case of moving subjects, where long exposure times are not indicated. But then, it just a matter of allowing more light, maybe by adding an external flashgun to your camera (use a diffuser for shadow free illumination).

Close-up of a flying ladybug - Taken using an extension tube and a 50mm lens — Photo by Luca5

Photo ©© Luca5




 

1 The dragonfly picture you see on this page required a very complicated technique to obtain, yet the macro principle remains the same, nonetheless. (↑)





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Comments

  1. By Morgan Glines, on October 05, 2011, at 02:46 AM
    One other plus is that they cost a whole lot less than a macro lens (~$100 USD for a set) versus ~$400. And, if you do finally get a macro lens, you can use it with the tubes to get additional magnification.




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