Extension tubes are designed to enable a lens to focus closer than its normal set minimum focusing distance. Getting closer has the effect of magnifying your subject (making it appear larger in the viewfinder and in your pictures). They are exceptionally useful for macro photography, enabling you to convert almost any lens into a macro lens at a fraction of the cost while maintaining its original optical quality.
The extension tubes have no optics. They are mounted in between the camera body and lens to create more distance between the lens and film plane. By moving the lens father away from the film or CCD sensor in the camera, the lens is forced to focus much closer than normal. The greater the length of the extension tube, the closer the lens can focus.
The KENKO AUTO EXTENSION TUBE SET contains three tubes of different length, a 12 mm, 20 mm, and 36 mm, which can be used individually or in any combination to obtain the desired magnification. Kenko also makes a UNITUBE 12 mm or 25 mm which can be purchased individually.
Kenko's Auto Focus extension tubes are designed with all the circuitry and mechanical coupling to maintain auto focus and TTL auto exposure with most Canon lenses given there is enough light to activate the cameras AF system properly.
1. When using extension tubes the lens will not focus to infinity. The focus range will be greatly limited to a very close focusing distance.
2. There is light fall off when using any extension tube, sometimes the equivalent of 3 f-stops of light is lost when using multiple extension tubes together. This light lost can affect the camera's ability to auto focus. Manual focusing is recommended should the lens begin to "hunt" (not lock onto the subject).
3. Kenko Auto Extension Tubes are not auto focus compatible with Canon EF-S lenses
New DG Series have upgraded "Gated-Array" circuitry to work better with the digital SLR's and some of the the new digital only lenses. They still work the same with film SLR Cameras and lenses as well
Most Liked Positive Review
Great for long lenses (over 100mm)
Seeing as I'm a budding entomologist and all-around nature lover, I bought a 100mm macro, and I was completely blown away at the magnification and image quality. Once I took about 10000 shots, however, I wanted more. I wanted to take pictures of even smaller things, or bring out the details of some "larger" insects. I love the image quality of my macro lens, so I was glad that these tubes preserve the quality, and still gave me ~2:1 magnification (just over twice as much as the macro lens onl...View full Review
Seeing as I'm a budding entomologist and all-around nature lover, I bought a 100mm macro, and I was completely blown away at the magnification and image quality. Once I took about 10000 shots, however, I wanted more. I wanted to take pictures of even smaller things, or bring out the details of some "larger" insects. I love the image quality of my macro lens, so I was glad that these tubes preserve the quality, and still gave me ~2:1 magnification (just over twice as much as the macro lens only). I am now able to see the complex eyes of ants, and capture in full detail the structures of a beetle small enough to fit on my fingernail. However, it does have it's drawbacks. The DOF (Depth Of Field, the part of the image that's in sharp focus) is minimal when you use the 100mm macro, and it's even narrower when you use the extension tubes. It's not the tube's fault, physics is to blame here. So if you use the tubes (and you'll really notice it if you use all three at once), you'll freak out when you get softer images than you did when you used your macro lens. This is due to the narrower DOF, and if you stop down past f13 on a digital camera (I'm talking about APS-C size sensors, 1000D, 300D-450D and 10D-50D models), diffraction may soften the pic up for you. It's not really that bad, though, although it is noticeable if you're a "pixel-peeper" (you like to look at the images at 100% on the screen). I can assure you that even if you print it poster size, the softness won't be too big a deal. You can always sharpen it in post-processing. I also tried the tubes on another lens, a 50mm f1.4. If you plan on using this, I would only recommend the 12mm tube, or in some cases (when you have lots of light), the 20mm tube. I wouldn't recommend any combination of tubes because the working distance is too close to be of any use. The 12mm allowed me to get some nice closeups, but any combination of tubes had me focusing barely an inch or less in front of the subject, and all 3 tubes just can't focus (due to optical physics, the focus point would be inside the lens). So if you plan to use it for a 50mm lens, I suggest getting only the 12mm tube (or the 20mm tube only if you can get very very close to your subject) Most insect macros are out of the question. Oh, one more thing about using them with a 100mm macro lens: the AF works fine with the 12mm and 20mm tubes (separately). It's ok using any other combination, and it's almost useless when using all three tubes unless you have incredibly good lighting. I recommend manual focus and an external flash to get some great pics. All in all, I would definitely recommend this to anyone interested in getting closeup shots using their existing lenses, provided you are aware of its shortcomings. To take advantage of all three tubes, I would suggest only using them on a lens with a focal length of at least 100mm.
Most Liked Negative Review
A very basic extension tube set
These tubes don't inspire my confidence, due to lower-grade materials, lower-grade finish, and lower-grade fit. They're cheap, in my opinion, but as simple lens spacers only, they get the job done. I have doubts about the longevity of the contacts, but have not used them long enought to confirm that suspicion. In my opinion, if you're looking for heft, quality, dependability, and pride of ownership, look somewhere else.
Reviewed by 48 customers
I primarily use the extensions for macro photography and so far have loved the results.
But it still feels cheap build, very plastic. So not recommend to put behind heavy lens
For the price i dont think you can go wrong, when stacking it can become a little bit shakey, but its just an extender no need to pay 300 for something that just extends your lens.
The tubes worked well with all my Canon lenses, either as a stack of tubes or individually. Claims of Autofocus compatibility seem pretty well overstated, though. AF did work with single tubes and sometimes with two together, but I could never get it to work with all three tubes. All my lenses are Zoom which adds more complexity. I used Manual focus and Zoomed to get a good focus...and the pictures turned out great.
I've used these tubes for macro photography. Not much to go wrong with them, they're tubes. They are well constructed and they work well.
I wanted to do macro photography, especially bugs and flowers. I haven't had the summer yet to practice, but with my first efforts, I am pleased.
Use with my 70-200L F4. Great for getting close and easy of composition vs my 100mm F2.8 Macro. Use with 100mm F2.8 Macro for real close. For Wild flower I really like this product with the 70-200 over the 100mm b/c of easy of composition.
These are a great alternative to more expensive tubes. I really enjoy the results.
I've always loved playing with macro photography, and when I learned about tubes, these were the first ones I saw. After a great deal of shopping around, these were the ones I came back to. Some tubes are just tubes made from crummy plastic or are otherwise made poorly, while some are greatly overpriced for what they are. These tubes are photography equipment, not a cheap novelty, and they are not overly complicated with a price to match. I feel the construction is quite good. When all tubes are stacked, you can wiggle them ever so slightly, but it's hardly noticeable. The only concern I had was when mounting the tubes to the camera it seemed like a tight fit, but I have had no problems at all. They've helped me produce some very interesting photos. I think they're great for the price, and was actually surprised at how relatively inexpensive they were.
Extension tubes are a great investment if you can't afford macro lens