Kenko Extention Tubes and Auto Focus

Hi All,

 

I'm looking into purchasing the set of Kenko Extension Tubes for my Canon 80D https://www.bhphotovideo.com/c/product/375102-REG/Kenko_AEXTUBEDGC_Auto_Extension_Tube_Set.html.

 

I have some Canon EF lenses and some EFS lenses. Here's my question: will the Kenko tubes provide auto focus for the EFS lenses? I've searched the Kenko website and various forums and can't get a definitive answer. I know the tubes will physically fit the EFS lenses but am not sure if they will provide for auto focusing.

 

Please help.

 

Thanks.

I haven't gone back and looked it up, so this is as far as I "remember" - a perilous basis for action, BUT

 

1. the tubes have to have the physical connection for the AF circuit, of course.
   
2. depending on the camera body and model, there are limits to AF as the effective aperture is reduced. Same sort of limitation as with telextenders. Most consumer-grade bodies shut down AF beyond a certain effective aperture. Th "1" models will go further into the darkness.
   
3. As for the EF-S lenses specifically, I think they'll work, given the above limitations.
   

I have a set of Kenko tubes for my Nikon system. They do not support autofocus with my non-macro, not-very-fast lenses. I don't know whether that is due to an inherent deficiency in the system, or if the effective maximum aperture is too small to allow autofocus to work. This has not been an issue for me. (And I don't use them much at all since purchasing my 105mm/2.8 Micro Nikkor.)

 

From the add you linked:

"These Kenko Auto Extension Tubes retain auto focus capability with Canon AF lenses providing the effective aperture stays at f/5.6 or brighter." This effective aperture will be your limiting factor.

 

Also, take note that what these extension tubes do is allow closer focus than normal for the attached lens. It is not useful to use these with a close-focusing macro lens, since the near focus point is so close to the front lens element that the lens can begin to shadow the subject. If you are looking for a cheap (and concomitantly less effective) method of increasing the performance of a macro lens, then look at a tele-extender. As JDM notes, autofocus will be impacted the same way by the effective maximum aperture. There have been a number of discussions about this, and I have previously posted some examples, but I haven't figured out how to access them in the new PNet format. Sorry.

Thank you gentlemen. I've placed an order through Adorama (the are having a special sale price of $79.95; regularly $109). I'll let you know what I've found out. While I do have a Canon 100mm macro lens, I think I'd prefer the lighter weight of the tubes for travel.

I'll see if I can find my examples for comparison. I have had a 55mm/2.8 Micro Nikkor for years that I used with a 2x tele-extender. I also have other lenses that I used with the extension tubes, and now my 105mm/2.8 Micro Nikkor. What I found was that the native resolution of the macro lenses matched or exceeded the resolution of any combination of other lenses combined with tele-converters/extension tubes. Still, the extension tubes are the light-weight/compact solution for travel, if you don't want to carry the big macro lens, so long as you are willing to settle for the (inevitably) lower IQ. Good luck!

Yes, I use them very often with my XSi and the kit 18-55 IS without any problems. You lose infinity focus and the range of focusing distances can become small. Many times it's easier at the macro distances to move the camera closer or farther to get focus.

 

You didn't say what lens you are going to be pairing them with. You get the most magnification with shorter lenses. With the kit lens and the 24mm tube you end up with the close focal point being inside the lens at 18mm.

I find that extension tubes are most effective with "normal" and longer lenses. Used with a wide angle lens, the magnification doesn't improve much in a practical sense, because the working distance (front element to the subject) gets very small or vanishes altogether. In a compound lens, the tubes extend the distance to the rear node distance, whereas the working distance is measured from the front node, which can lie inside or even behind the lens.

 

An extended 50 mm lens is best used to copy documents or slides, or to photograph inanimate objects (e.g. coins, stamps) A 55/2.8 Micro-Nikor is limited to 1:2 magnification. Used with a PK13 extension tube (27 mm), the maximum magnification extends to 1:1, but the working distance is less than 4". The camera lens tends to shade the subject at that distance, and critters are likely to get spooked.

 

For closeups in nature, which rarely exceed 1:4 magnification, I prefer to use a longer lens, at least 90 mm. Many, like a Leica Summicron 90/2, AFS 70-200/2.8 or AFS 300/4 focus no closer than 1 meter, about 1:8. The Kenko set, when combined, increases that to 1:4 or better. You can use extension tubes with zoom lenses too, but they are no longer even remotely parfocal, which means you must refocus and recompose if the zoom is changed. The Nikon 80-180 Zoom-Macro is the only exception in my experience. Most companies make macro lenses in the 100 mm class, so use of extension tubes is moot if you have the budget.

 

I find extension tubes extremely useful for medium format (Hasselblad) photography. A 16 mm tube on a 180 mm lens gives you a 9"x9" subject area and a 16" working distance. A 32 mm tube covers an area the size of a postcard. At that magnification, curvature of field and other artifacts are minimal. This is comparable to using a 135 mm lens on a 35 mm camera.

 

A tele-extender works well with compatible zoom lenses, such as a Nikon 70-200/2.8, for moderate "closeups". You can only focus to 1 meter or so, but the magnification changes by the tele factor (1.4, 1.7 or 2.0), at the expense of a stop or two exposure. The good thing is, the lens remains nearly parfocal. (Consumer level zoom lenses compromise on focus to keep cost and weight down. Professional video lenses must be parfocal, but cost $3500 to over $150K.)

Edited March 24, 2017 by Ed_Ingold

. . . I'm looking into purchasing the set of Kenko Extension Tubes [Kenko Auto Extension Tube Set DG] . . . I have some Canon EF lenses and some EFS lenses. Here's my question: will the Kenko tubes provide auto focus for the EFS lenses?

 

I have those tubes and have used them with a few EF-S Lenses. I understand that you have already bought the Tubes but the last comment might be particularly useful to you.

 

The auto Focus System will function, but it depends on the lens and the lighting situation as to how accurate it works and locks to accurate focus. Getting the lens / camera position near the point of sharp focus alleviates hunting and predicates better accuracy.

 

Manual Focus is very accurate by comparison to using AF on lenses which have a small Maximum Aperture.

 

My guess is by “lighter weight” and “EF-S” that you might use the tubes with a kit zoom lens – if so, then be careful to recognize that some (many?) of the kit zoom lenses do NOT employ Full Time Manual Focus, so ensure that you change the selector switch to “MF” if you chose tio use Manual Focus.

 

WW

I'll see if I can find my examples for comparison. I have had a 55mm/2.8 Micro Nikkor for years that I used with a 2x tele-extender. I also have other lenses that I used with the extension tubes, and now my 105mm/2.8 Micro Nikkor. What I found was that the native resolution of the macro lenses matched or exceeded the resolution of any combination of other lenses combined with tele-converters/extension tubes. Still, the extension tubes are the light-weight/compact solution for travel, if you don't want to carry the big macro lens, so long as you are willing to settle for the (inevitably) lower IQ. Good luck!

Here is the link to the earlier discussion, including sample photos: https://www.photo.net/discuss/threads/macro-lens.514157/#post-5466864