Terry

I have tried to use a kenko extension tube set on my Canon 30D and my canon 7d and on my rebel xsi and with numerous lenses and I just can!t get them to work, what am I doing wrong they are brand new.

Morning Star Loc: West coast, North of the 49th N.

Could you be a bit more specific, please.
Did you get the right set for your Canon cameras?
How are you trying to use them? Are you moving your camera (and with that, the lens) closer to the object to be photographed?
Is the tube you're using, mounted properly?
Are you using the right f/stop?
There's some more information if you scroll down a bit on this page:
https://www.bhphotovideo.com/c/product/375102-REG/Kenko_AEXTUBEDGC_Auto_Extension_Tube_Set.html

Some more information here:
http://cdn2.bhphotovideo.com/lit_files/113153.pdf
http://shuttermuse.com/ultimate-guide-to-extension-tubes/
http://www.eos-magazine.com/EOS%20Collection/shop/Resources/Extension%20tubes%20(2010).pdf
https://www.digitalphotomentor.com/hot-to-use-macro-extension-tubes/

Good luck!

CHG_CANON Loc: the Windy City

Define "work".

Do you mean the autofocus doesn't operate? The Kenko models should to this. If not, that's a problem. Are you using the Kenko Extension Tube Set 12,20,36 DG, for Canon EOS EF Mount?

Or rather, do you mean autofocus works but you cannot get the lens to focus? Here we need to assure you understand what an extension tube does to your lenses, i.e., purpose. Assume a lens that has a max focal length of 200mm. Without mounting the tube, the closest you can focus is onto something that is about 4-feet (1.2m) away. The same lens without the tube, you can easily focus on an object at an "infinity" distance away. But, with the 20mm Kenko tube mounted between the camera and lens, you should find that you can now focus on an object that is only 2-feet away*. And, you no longer can focus on anything at a distance greater than 5-feet away*.

*These value are illustrative, actual distances depend on the specific lens and tube size selected.

Please review these two scenarios and confirm the issue or provide a more detailed description of your experiences, including some or all of the lenses involved. Confirm too the specific model of Kenko tubes and they're the EOS EF mount version.

Mac Loc: Pittsburgh, Philadelphia now Hernando Co. Fl.

Did you look on the Kenko web site to see if the are compatible with the lenses and cameras you are trying to use them with?

Terry

I checked for the extension tubes for canon and it is the right one12mm,20,36mm DG if I try just one tube 12mm I can focus with manuel focus but not auto focus, auto doesn!t work with any ring. I have a canon17-85 a canon 55-250 and a canon 70-200 f 2.8 so they don1T work with any although the canon sight says they are compatible.

CHG_CANON Loc: the Windy City

Canon would never comment on the performance nor compatibility of a 3rd party product. However, the various sites that sell the Kenko tubes all indicate they retain autofocus when used with Canon EF and EF-S lenses. You should contact the vendor where purchased and discuss return and / or refund options.

cthahn

You do not explain how you are using them. There is nothing to go wrong with and extension tube. Read some articles on extension tubes and understand them.

Thomas902 Loc: Washington DC

"I have a canon17-85 a canon 55-250 and a canon 70-200 f 2.8 so they don1T work with any" Terry Extension Tubes work primarily with normal length primes... i.e. a 50mm optic. How many 1:1 micro lenses are zoom optics? None, period! Yes there is an old "D" version "micro" Nikkor zoom but it is definitely NOT 1:1

It is also imperative that the tube(s) be attached to the camera body first...

BTW: I have the Kenko Automatic Extension Tube Set (DG) for Nikon AF it is works flawlessly on my AF 50mm f/1.8D and AF-S 50mm f/1.4G Nikkors... Both of these lenses are "Primes" and yes I read the instructions Kenko packaged with this set VERY CAREFULLY first... Enough said...

Best Advice? Purchase a micro (i.e. macro) lens from Canon...

Terry

Thanks, I must have countless hrs. messing around with this problem. Maybe I will buy a macro.

mwsilvers Loc: Central New Jersey

Where exactly did you read that Canon says that Kenko extension tubes are compatible? While they should be compatible, Canon would never indicate that in print, and even Canon's support staff generally avoids discussing compatibility with third party products. Second when you say auto focus doesn't work are you saying it doesn't achieve focus, or its not even trying to achieve focus? What is your intended reason for using the extension tubes. I just want to confirm that you understand they are intended to allow your lenses to focus much closer to your subject and as a result they act as sort of a poor man's macro lens. I hope you haven't confused them with similar looking teleconverters which are used to increase the focal length of a lens.

Terry

I have checked on the compatibility for the extension and they are supposed to fit all 3 of my canon cameras, and I do know the difference between extension tubes and teleconverters. Thanks for your follow up. I will keep all informed on my progress.

mwsilvers Loc: Central New Jersey

Your problems are most likely due to user error. Without giving us more specific details on the issues you are having and how you are using these extension tubes we cannot help you.

jeep_daddy Loc: Prescott AZ

That's the answer. Get the 100mm Canon macro lens. Either one is very nice - I've owned both and still own the L series lens.

CHG_CANON Loc: the Windy City

Dedicate macro lenses have attributes that by design make them a better choice, but your 70-200 is an excellent candidate for use with an extension tube as a pseudo macro lens. The image below was captured with the 70-200 f/4L and the EF 25 II Extension Tube. Assuming the Kenko tubes maintain AF, a regular argument I see made is that Kenko's "open air" in the tube is just as good as Canon's while being a lot cheaper. That is, the tube doesn't contain any glass / optics so why not go with the cheaper version to move the lens further away from the sensor?

Orb Weavers by Paul Sager, on Flickr
http://farm5.staticflickr.com/4506/36642390354_d4c593d627_b.jpg

mwsilvers Loc: Central New Jersey

One reason to go with the more expensive Canon version is build and fit, epecialliy important If being used with a lens a bit on the heavy side. I've read a few comparitive reviews that indicated the Kenko connection to the camera and lens was not as rigid as with the Canon extensions. I have a Canon 12mm extension tube which I primarily use with the 35mm f/2 IS USM lens. The combo attached to my 7D Mark II is absolutely rigid.