Cheap electronical macro extension tubes for Canon EF mount

January 6, 2019

So just for fun, I decided to try out some macro equipment. There’s many ways of doing macro photography, ranging from specialized lenses, to just reversing a lens. I decided to go with the cheap middle path, macro extension tubes.

The extension tubes / rings are like hollow tubes that physically moves the lens further away from the camera. What they essentially do is modify the focusing distance of the lens projection against the sensor, i.e. you can focus more closely, but you lose infinite focus.

The tubes in themselves are nothing fancy, they can be made of any material, and the manufacturing quality doesn’t really matter since they don’t have any optical properties (they don’t contain any glass).

Canon 5D, Canon EF 50mm f/1.8 II @ f/13, 1/160s, ISO100, 13mm + 31mm @ 0.65x magnification, with Flash

The main trade-off (although there are other as well) with extension tubes versus actual macro lenses, is that you tend to have to get very close to the subject with the lens. Which in some cases (or in most cases) ends up with the lens and camera overshadowing the object, i.e. it gets very dark. The only real way of combating this is by using a strobe or a flash to illuminate the subject.

It’s worth noting, that for some camera systems, like Canon EF, which have an electronically controlled aperture, you might want to opt for tubes that have the electrical wiring for connecting the lens with the body.

I decided to go with an electrical set (i.e. has the electrical Canon EF connections for auto-focus and aperture). The box that arrived says “3-piece macro extension tube set”, but it was sold under the name “Lens Adapter Mount Auto Focus AF Macro Extension Tube Ring for Canon EF-S Lens T5i T4i T3i T2i 100D 60D 70D 550D 600D 6D 7D lens” on Aliexpress.

From what I can tell, most, or all of them, are the same. The rings come in three sizes, that can be combined in any way, 13mm, 21mm, and the largest, 31mm.

I paid a total of 9.45€ (with free shipping), and it took about 4 weeks for the adapters to arrive.

The build quality is about what you can expect for something that retails for a McDonald’s meal. Playing around with the kit, the physical connections are quite flimsy, and it’s hard to tell when it’s actually locked in place, there’s a large room of play.

Canon 5D, Canon EF 50mm f/1.8 II @ f/13, 1/160s, ISO100, 13mm + 31mm @ 0.65x magnification, with Flash

The auto-focus seemed to work with all of the rings, but for some reason the aperture can’t be set with the largest ring (31mm), instead the camera locks up with an error. I got around it by setting the aperture prior to adding the rings, using the depth-of-field-button-hack to lock the aperture to the lens (holding in the preview button, whilst unscrewing the lens).

Working with macro tubes are a bit weird, since they can modify any lens, there’s no real golden rule for tube sizing. Depending on the focal length of the lens, the magnification, the near focusing, the macro properties will be different. From what I’ve played around, I’ve found out that the longer the lens does not equal better “macro-bility”, quite the opposite actually.

Canon 5D, Canon EF 50mm f/1.8 II @ f/13, 1/160s, ISO100, 13mm + 31mm @ 0.65x magnification, with Flash

After playing around with the lenses I have at home, I decided that my Canon EF 50mm f/1.8 II was my best candidate. I found this nifty webpage, that’ll go in to more detail about extension tubes. It also offers a really nice calculator of which you can use to calculate the expected magnification given that you know a couple of key values for that lens.

Anyway, back to the cheap-o extensions tubes, even though the build quality is quite horrendous. And the fact that the electrical connections are not really working, I’d still say they were worth the money I paid for them. I’ve seen a lot more expensive tubes that you can buy within the EU. For example the Canon version, Canon Extension Tube EF 25 II, retails for around $140. And that’s a single tube at 25mm (not to be confused with Canon Extender, which modifies the focal length of a lens).

You can probably find cheaper extension tubes as well on Aliexpress or Ebay. Especially if you opt for a non-electrical one, and in hindsight – with the issues I had – I would almost recommended those (even though I haven’t used them), just because they are so simple in nature, but I digress.

I’d say they are worth the money, at least for just horsing around.