Extension tubes for macro photography – Canon Test

Author: Iacopo I. Date: Thursday, September 8 2010 Read other reviews in: Accessories Share with your friends: Share on FB   Tweet this

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Personally I’ve been fascinated by macrophotography since I started taking the first photos with my first SLR camera. As a student, always without money, I had to find alternative solutions to expensive macro dedicated lenses and so my first experiments were based on the use of ordinary magnifying glass founded at home. Some time after my father gave me (and to himself) a so wonderful inversion ring which I could mount on the camera body tu use the 50mm to take mi first macros. The issue were a lot due to the short depth of field and the loss of automatism. Since then many things and cameras have changed till to my current coupled Canon EOS 7D and the legendary Canon EF 100mm f/2.8 Macro USM. The problem is that after going to the macro you want to go further in the short range, and for this reason some time ago I decided to buy a set of extension tubes for macro photography.

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The extension tubes are very simple tools but ate te same time very useful. These are litterally empty tubes, without optical elements (no lenses) that have to be interposed between the camera body and lens to introduce spacing between the lens and the image plane (sensor or film). More distance is introduced and more the magnification encreases at a cost of losing in the brightness and loss of focus at long distances and infinite. There are two different types of Extension tubes on the market, with and without extension of the electrical contacts (see the picture). In case of extension of the electrical contacts the lens will continue to communicate with the camera body for autofocus and settings communication.

For Canon there are many types of tubes on the market that differs in quality, length and price. The genuine Canon 12mm and 25mm are marketed at prices around 120 euros each. Another set of well-known and very well spoken are manifactured by Kenko and the set is composed on three tubes of 12mm, 20mm and 36mm at a reasonable lower price. Personally I decided for a set much cheaper tubes set with the presence of electrical contacts, so I bought on e-bay a new set of SEIMAX for Canon AF at a price that was around 50 euros. The set is composed of three tubes of 13mm, 21mm and 31mm. The construction quality is enough good to fill my satisfation, but I use them almost in studio. When I decided I supposed that any brand should be the same because of the lack of any optical element and I choosed the cheaper set with electrical contact. I must say that I feel fine with my decision, the contacts have always worked perfectly and once assembled the tubes are fairly robust.

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The scoper of this article is to point out the magnification ratio of each single tube and them combinations. Below the picture taken without tripod with my Canon EOS 7D and the Canon EF 100mm USM macro f/2.8.

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The images have not been cropped but only post elaborated to increase the contrast to put the attention on the real dimension of the reproducted surface. Each square is 1mm x 1mm in dimension. The first image has been taken without any extension tube.

Canon EOS 7D + Canon EF 100mm USM Macro f/2.8 (21,5mm x 14,5mm about)

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Canon EOS 7D + Canon EF 100mm USM Macro f/2.8 + tube 13mm (18,5mm x 12,5mm about)

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Canon EOS 7D + Canon EF 100mm USM Macro f/2.8 + tube 21mm (16mm x 10,5mm about)

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Canon EOS 7D + Canon EF 100mm USM Macro f/2.8 + tube 31mm (14,5mm x 10mm about)

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Canon EOS 7D + Canon EF 100mm USM Macro f/2.8 + tubes 13mm and 21mm (14mm x 9,5mm about)

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Canon EOS 7D + Canon EF 100mm USM Macro f/2.8 + tubes 13mm and 31mm (13mm x 9mm about)

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Canon EOS 7D + Canon EF 100mm USM Macro f/2.8 + tubes 21mm and 31mm (12,5mm 8,5mm about)

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Canon EOS 7D + Canon EF 100mm USM Macro f/2.8 + tubes 13mm, 21mm and 31mm (11,5mm x 7,5mm about)

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• Description: Extension tube set for macro photography review containing the results of a test done to evaluate the magnification factor on a Canon EOS 7D with a Canon EF 100mm USM macro f/2.8 lens.
• Italian: http://www.mvmnt.it/it/recensioni/accessori/141/tubi-prolunga-per-macrofotografia/