KenkoAuto Extension Tube Set DG 12mm, 20mm, and 36mm Tubes for Canon EOS AF Mount

The Kenko Macro Automatic Extension Tube Set for Canon EOS is a set of 3 extension tubes that you can mix and match to give you different levels of "magnification" (more on this in a bit). You get 12mm, 20mm and 36mm tubes that you can use singly or mix and match to give you a maximum of 68mm.Extension tubes do not contain any glass/optics and are designed to enable a lens to focus closer than its normal minimum focusing distance. As such they effectively magnify your subject. The extension tubes are mounted between your lens and the camera body to create more distance between the lens and your sensor. By moving the lens further away from the camera sensor, the lens is forced to focus much closer than normal and your image is essentially cropped. The greater the length of the extension tube, the closer the lens can focus. Basically the sensor captures a smaller amount of the image with the rest of the image being outside of the sensor.You have to take into account the focal length of your lens when applying extension tubes. For example, if you have one of the 50mm Canon primes, you cannot use the full 68mm of the extension tubes as you will never be able to focus the object.I done a great deal of research into extension tubes and which ones to get before deciding to go with the Kenko Automatic tubes. The automatic part of the Kenko set is that each tube has a series of connectors which relay information from the camera to your lens and vice vera. Thus all the EXIF data is passed on, auto focus, aperture etc. all work just as if the lens was connected directly to your camera.The Kenko tubes work with both APS-C and full size cameras and lenses (basically EF (Full Frame) and EF-S (APS-C) lenses).I've tried out a variety of lenses with this Kenko set including but not limited to 18-135 EFS, 70-300EF and 100L EF Macro lens. All the lenses I have tried have worked without problem. I have even used this extension set along with a Metabones III adapter to on my Sony A7 full frame again without incident.By giving you three separate extension tubes you have much greater flexibility in the amount of magnification you desire and working with a proper macro lens (e.g. Canon EF100L 2.8 USM Macro) you can get extremely close into a subject. You can however use these lenses to turn a non-macro lens into a sort-of macro if you don't want to spend the money specifically on a macro lens (if you are interested in macro photography you really do need a specific macro lens). For example I used these extension tubes with my 70-300mm lens to get some quite detailed and sharp images of flowers and insects.When shooting macro, you have a very narrow depth of field and it is also harder to keep a subject in perfect focus (a tripod really is a must). Using extension magnifies these effects.The only downside to the Kenko set of extension tubes if the price. They are well constructed, fit tightly and work very well but I still think $200 is a little much when all they really are is a set of tubes and connecters (no optics).Overall a great addition to a macro photographers toolkit and I carry these around in my camera bag everywhere I go.

I bought these in part because I switched to a full-frame camera, making my Tamron 90mm macro lens considerably less useful. So far I have used them with the Tamron 90mm macro (12mm extension) to make it a functional macro lens for insects again, and with the Canon 300mm F/4 (36mm). I almost always shoot handheld, using a flash for closeup macro but not with the long lens.The macro + 12mm extension is a great combination, making it possible to again use the macro lens for larger subjects. Autofocus still works fine, although I don't always use it for macro, depending on what I'm photographing. The 300mm F/4 + 36mm extension is a perfect dragonfly setup for most species, allowing me to get close enough to fill the frame on larger species. Again, autofocus works fine, as does aperture (unlike with macro, where I usually use f8 or f11, I use a variety of apertures for dragonflies) I haven't yet tried stacking more than one extension tube, but expect that will allow me to get closer to damselflies and small dragonflies, while still retaining more working distance than I would get with a macro lens.I haven't yet tried the extension tubes with my 35mm reverse macro set, but I will soon. The Kenko tubes are solid and slip on and off easily, and seem to be well-made. The one potential issue is that it is possible to bump the release lever if you're not careful. It's unlikely that the lens will fall off, but it's a good idea to be careful and aware of the possibility.Honestly, I didn't fully understand the purpose of extension tubes before I got them, but now I wouldn't go without them. They're incredibly useful. Just be aware that they function by *reducing your working distance*. If you want to magnify more without getting closer to your subject, you want extenders/teleconverters or diopter filters, not extension tubes. If you want a large depth of field with your subject sharp all the way through...no lens or extension tubes will give you that, but you might want to google "focus stacking" (it's a physics problem). If you are ONLY planning to do reverse macro, where you lose autofocus and control the aperture via a manual aperture ring, you don't need the electronics in these and can buy much cheaper, electronics-free extension tubes.