Disappointed in Kenko DG extension tubes for canon

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jzucker
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Disappointed in Kenko DG extension tubes for canon

Post by jzucker »

Very flimsy plastic and the mount is very loose. Mounting my 200 mm lens on the 3 tubes is a joke. It feels like it's going to come loose from the lens or body. Barely works with my 100mm 2.8L macro.

Rylee Isitt
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Post by Rylee Isitt »

I don't have this problem with mine. Mine are also made out of metal, with a metal mount. The plastic is just finishing over a metal barrel.

They are called "Kenko Automatic Extension Tube Set DG".

I purchased mine about six years ago, mind you. Maybe they've changed the construction since.
Last edited by Rylee Isitt on Sat May 12, 2012 12:43 pm, edited 1 time in total.

DQE
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Post by DQE »

I wonder if you haven't acquired counterfeit Kenko tubes? Everyone I have followed in various macro forums seems to be happy with their Kenko tubes.

From reading the descriptions at some major photographic stores, they should still be made of metal, as best I can understand. The price seems to be about $180 US dollars.

I hope this speculative suggestion is helpful.
-Phil

"Diffraction never sleeps"

rjlittlefield
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Post by rjlittlefield »

My Kenko tubes are about 2 years old now (March 2010). They are made of plastic coated metal, but they do have a feel much like jzucker describes. As shown in Rylee's photo, the tension springs in the female part of the bayonet are single-ended cantilevers. They're not nearly as stiff as the double-ended springs used in my Canon body. The Kenko tubes work fine for my applications, but for sure if I tried to hang a heavy lens off them, the tension springs would flex and the lens would sag.

I have no personal experience with brand-name Canon tubes. From the photo at Adorama it looks like they use the same type of cantilevered spring. I recently heard from a pro at a conference that the Kenko and Canon tubes look like they came from the same manufacturing line, but I can't confirm that. If anybody else has contact with both sets of tubes, I'd appreciate comment.

--Rik

Chris S.
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Re: Disappointed in Kenko DG extension tubes for canon

Post by Chris S. »

jzucker wrote:. . .Mounting my 200 mm lens on the 3 tubes is a joke. It feels like it's going to come loose from the lens or body. . . .
My Kenko tubes are 6-8 years old. I generally like them, but they do not mount as tightly as the one old Nikon brand tube I have. There is a bit of play to my Kenko tubes, which is generally not too objectionable when a single tube is used. But when two or three tubes are used together on a long lens, there can be more play than I'm comfortable with. When I used to hunt dragonflies with a 300mm f/4 or 80-400mm zoom on on two or three Kenko tubes, there was enough slop to be very annoying. I never felt that anything was going to come loose, though.

If I ever get back to dragonfly photography (unlikely, as dragons have become a photographically mature subject), I'd probably clamp both camera and lens to a long A-S style rail to make a more stable rig.

--Chris

Rylee Isitt
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Post by Rylee Isitt »

I've used my Kenko extension tubes with a 100-400mm L a few times to photograph dragonflies at a pond. It was more just me being silly than doing serious photography, but the Kenko tubes worked OK. They weren't a perfect, rock solid connection though. But holding the lens in one hand and the camera in the other made it workable, more or less.

Rylee Isitt
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Re: Disappointed in Kenko DG extension tubes for canon

Post by Rylee Isitt »

unlikely, as dragons have become a photographically mature subject
That's sort of a depressing thought, but I'm not sure it's reason to hold yourself back (unless you have no shortage of other, less explored subjects). If you fiddle with Google Earth, you quickly discover that basically every spot on Earth that's conveniently accessed has been photographed from multiple angles by numerous people. And yet, landscape photography continues to thrive and offer new perspectives, even on well-photographed places.

Perhaps the same is true for dragonflies?

Chris S.
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Re: Disappointed in Kenko DG extension tubes for canon

Post by Chris S. »

Rylee Isitt wrote:
unlikely, as dragons have become a photographically mature subject
That's sort of a depressing thought, but I'm not sure it's reason to hold yourself back (unless you have no shortage of other, less explored subjects). . . . Perhaps the same is true for dragonflies?
Rylee, to be sure everyone understands, my comment reflected one of my personal viewpoints regarding the art of photography. It was not an exhortation for that everyone should view photography as I do.

I recently had an airplane seat next to a person well-educated in the visual arts. We began discussing the artist Georgia O'Keefe, and my seatmate described much of O'keefe's work as "redundant." While I'd held similar opinions to my seatmate, I was unfamiliar with her use of "redundant" as a term of art to describe, in this case, the arts. This seatmate's underlying point rang a strong chord with me. In Georgia O'Keefe's work, there are some legitimately novel creations, but also a ton of repetition of whatever was popular with purchasers (think about her countless paintings of the Pedernal). To me, Georgia O'Keefe's novel statements were art, but her redundant works seem not art so much as a a way of making a living.

My own hope is to avoid producing images that look like any seen before. This is difficult, but otherwise, why bother? Might as well take up paint-by-number sets. For most of my subjects, before I make an image, I do a Google image search to see what has been done. Any successful prior treatment is off limits, unless I think I can improve upon it. On the other hand, there is no shame in reproducing someone else's tour de force as a learning exercise or starting protocol (with attribution); embarrassment would be deserved only if presenting such an image as an example of one's own virtuousity.
If you fiddle with Google Earth, you quickly discover that basically every spot on Earth that's conveniently accessed has been photographed from multiple angles by numerous people. And yet, landscape photography continues to thrive and offer new perspectives, even on well-photographed places.
Very much agreed, Rylee. I think a key here is to spend time in spots on Earth that are very inconvenient or dangerous to access, which is part of why I'm incommunicado for several months each year (or maybe I just like these places). While at its best level, landscape photography does indeed thrive, there are tens of thousands of dreck shots by photographic hacks whose images say nothing new. Or worse, they take an old shot, get out their Photoshop crayons (aka saturation), and make the scene look like a false wonderland of color--blech. Do a Google image search on Mesa Arch, Canyonlands, Utah, USA, to demonstrate what I mean. There are untold thousand of images that, mostly, have a very few set looks--and much false color. Why bother? On the other hand, when someone produces a truly fresh, visually compelling image of this spot, bravos are called for.

To bring this back around to photomacrography, dragonflies are very popular, and quite a body of outstanding work has been published, followed by a lot of work that seems redundant. For myself, I'd today be interested in pursuing dragons only if I had something new to say.

Many people are happy to produce well-executed visual cliches. But the best photographers don't do this. Artists like Monet, Van Gogh, Picasso, Matisse, Da Vinci, Shishkin, and Levitan* didn't copy others, but sought to better them. Should we be any different?

Sorry, Rylee--I'll get off my soapbox now. (Though many thanks for giving me a chance to climb up on it!) :)

Cheers,

--Chris

*--Edited to replace "Lermontov," whose name I had written, with "Levitan," whose name I had meant to write. While Mikhail Lermontov isn't entirely out of place in this list, he was of course a poet; Isaac Levitan was the landscape painter. Both names being three-syllable Russian names beginning with "L"--the brain does weird substitution tricks sometimes.
Last edited by Chris S. on Mon Apr 30, 2012 10:54 am, edited 1 time in total.

Rylee Isitt
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Post by Rylee Isitt »

Chris,

I can empathize with that viewpoint, and agree with it in principle. In practice, if I spent time trying to track down every photograph of a tarnished plant bug in an attempt to do something never done before, I'd wouldn't ever find time to pick up the camera. At some point you have to risk being unoriginal, I think.

Mind you, shooting extreme macro-photography gives us a technological novelty factor. I know lots of people who practice photography, but very few who practice macro-photography, and nobody (in person) who goes beyond 1:1.

But is technological uniqueness and choice of less overcooked subjects all that counts? My personal image-making has begun to trend more towards the informative side. If a dragonfly was doing something biologically interesting, or had an interesting backstory, I'd probably grab my camera - even if I had no hope at all of making a unique image, visually speaking.

Hey, I love these sorts of talks, and I think they are necessary for us to define our own artistic styles. I'll give people a soap box any chance I get.

DQE
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Post by DQE »

rjlittlefield wrote:My Kenko tubes are about 2 years old now (March 2010). They are made of plastic coated metal, but they do have a feel much like jzucker describes. As shown in Rylee's photo, the tension springs in the female part of the bayonet are single-ended cantilevers. They're not nearly as stiff as the double-ended springs used in my Canon body. The Kenko tubes work fine for my applications, but for sure if I tried to hang a heavy lens off them, the tension springs would flex and the lens would sag.

I have no personal experience with brand-name Canon tubes. From the photo at Adorama it looks like they use the same type of cantilevered spring. I recently heard from a pro at a conference that the Kenko and Canon tubes look like they came from the same manufacturing line, but I can't confirm that. If anybody else has contact with both sets of tubes, I'd appreciate comment.

--Rik
I have the Canon brand name tubes, but don't have Kenko tubes to compare them to.

I have always found the Canon tubes to be almost bank vault-like in terms of stability and rigidity/strength of attachment. If anything, the strength of the connection to the camera body or another Canon tube almost seems too strong. I have to use quite a lot of force when I use the tube's unlocking mechanism, but when it releases it does so positively and effectively.

I don't have any sense of mechanical weakness when used with my Canon 100mm macro lens or my Canon 70-300mm zoom lens. They lock to the camera body and also to any lenses I have used very solidly.

The body of these tubes seems to be plastic, with metal used in the outer camera and lens connection plates. There is generous use of what appears to be good flocking material inside the body. Concentric circles of anti-flare ridges are present on the outer surfaces of the tubes. The electrical connectors appear to be of high-quality materials, and I've never had any issues with this feature.

If photos of Canon tubes would help, I would be glad to try my hand and post some photos, but I fear that my product photography skills with such anti-reflective objects might prove to be lacking.
-Phil

"Diffraction never sleeps"

rjlittlefield
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Post by rjlittlefield »

I bet the description of behavior tells everybody what they'd like to know.

If you are inclined to try photographing the mechanism, I'd be interested to see it. But I sympathize with your concerns about the difficulty of getting a decent picture. I had to struggle to get this one. Finally succeeded by bouncing flash off a big reflector behind the camera, plus Photoshopping to tone down some ridiculously bright reflections that crept in anyway.

In my Kenko tubes, tension is provided by the cantilever spring marked here, starting at the orange arrow and exerting pressure at the red.

Image

--Rik

DQE
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Post by DQE »

Below are some ad-hoc, non-stacked photos of my Canon 25mm extension tube, for informational purposes only! As I suspected, my product photography skills are basically non-existent! The subject is Canon's 25mm extension tube.

I used a (non-L) Canon 100mm macro lens at f11 with my 5DII camera set at ISO 200, with a MT-24 twin-flash. I used a sheet of printer paper as the background. I only tried to capture the basic features of the 25mm tube. In the angled view, I focused on the brass electrical connection pins.

Moderate sharpening and "clarity" adjustment was done in CS5 Bridge. Resizing was done by default settings in Photoshop CS5.

One can see the reasonably thick (chrome-plated or polished stainless steel???) metal flange surfaces, the concentric rings/ridges anti-flare feature, the (poorly maintained and thus dusty) flocking material in the ring's interior, and the reasonably thick springs used to stabilize the tube attachment and alignment. In the first photo you can see the part of the unlocking lever protruding from the side of the tube.

The views provided are front, back, and angled so as to look inside the tube. I used Photoshop CS5's Bridge with its "fill light" slider to brighten the flocking material and other dark surfaces. I recovered some of the specular highlights on the shiny exterior flange surfaces by using the "recover" slider in Bridge.

Rik's photo is vastly better. I hope mine are at least somewhat functional and useful.

If anyone wants to see other views, etc,, even with my obvious aesthetic and other quality limitations, just let me know. I have an MPE-65 lens and can zoom in further if a view of something very small is needed.

-----------------------

I'm surprised to learn that there are opinions indicating that Kenko tubes may be unstable-feeling - previously, I had only heard positive, complaint-free opinions from others.

As I mentioned previously, if anything, my Canon tubes are surprisingly strong-feeling and seem to VERY rigidly couple to my lenses and camera bodies. Two tubes (12 + 25mm) work as rigidly as one and I've never had electrical connection issues with my 5D and 5DII camera bodies. However, this strength/rigidity doesn't create excessive stiffness or other difficulties with any credible uses, IMO. Perhaps this partially justifies Canon's usual high prices for this accessory? I think I'll now buy another 25mm tube so as to gain access to some additional magnification - I had been considering switching to Kenko with their 36mm tube, but now I'm concerned about the Kenko's tubes' rigidity and quality. Unlike Kenko, Canon doesn't sell a 36mm tube, only 12 and 25mm.

Image
Image
Image
Last edited by DQE on Mon Apr 30, 2012 5:33 pm, edited 1 time in total.
-Phil

"Diffraction never sleeps"

rjlittlefield
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Post by rjlittlefield »

Phil, thanks for the images. They're great for the job. My picture may be cleaner, but I had to work ridiculously hard to make it. The effort would have made no sense, except I got stubborn and decided to turn it into an educational experience. Anyway, about the tubes...

What I notice in your images is that the bayonet mechanism seems to be identical except that the Canon's spring has been opened wider during manufacturing.

I've read that it's not difficult to pry these cantilevers wider open to make them fit tighter. But I've not done that on my Kenko tubes because there was no real need and I didn't want to take the chance of going overboard.

--Rik

Craig Gerard
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Post by Craig Gerard »

Phil,

Thanks for uploading the images. They are very helpful.
I've read that it's not difficult to pry these cantilevers wider open to make them fit tighter. But I've not done that on my Kenko tubes because there was no real need and I didn't want to take the chance of going overboard.
I recently found the need to apply such an approach to an adapter. It's rather easy to do, but needs to be done in very small increments. I did post a related link some time ago.
http://www.photomacrography.net/forum/v ... hp?t=15376


Craig
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

Charles Krebs
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Post by Charles Krebs »

FWIW, when I was using Contax SLR cameras I had some accessories that had the same type of "cantilevers" on the three bayonet flanges, and presented the exact same problem. Prying them open just a bit helped for awhile, but they always got "sloppy" again. (And with heavier lenses there simply was not sufficient spring force in the metal to hold things tight enough).

While I don't necessarily strongly recommend my solution :wink: .. it did work for me and eliminated some frustration. I found a good rubber-band about 1/8"-3/16" wide that had about the same thickness as the gap. I cut small pieces and then carefully wedged and glued them (using a flexible rubbery type adhesive) into the space indicated below (Phil, hope you don't mind, I borrowed a piece of your tube image)

Image

As I recall in at least one instance it was too tight, and I needed to remove it and put in a more pliable/thinner piece of rubber. My primary concern was that the small piece of rubber might eventually work its way out and end up someplace very undesirable, but that never happened. It sure made for a very snug, slop-free fit.

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