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Kenko Extension Tubes

Discussion in 'Accessories' started by rdearth53, Jun 5, 2012.

  1. rdearth53

    rdearth53 Mu-43 Regular

    93
    Feb 4, 2012
    Wadsworth, Ohio
  2. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    I looked into them as well. Some people are reporting that they don't work electronically when stacked, just separately. Not sure if that's just with some lenses or all of them.
     
  3. humzai

    humzai Mu-43 Veteran

    410
    Apr 17, 2012
    KENKO confirmed that they work with all m4/3 lenses but soom might. Have.trouble with af. I hope to get a set soon.
     
  4. rdearth53

    rdearth53 Mu-43 Regular

    93
    Feb 4, 2012
    Wadsworth, Ohio
    Thanks! Any chance that you know it works well with the Pany 20/1.7 and Olympus 14-42 kit lenses?

    Sent from my Galaxy Nexus using Mu-43 App
     
  5. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Keith
    I have a hard time justifying the cost of the Kenko tubes over the basic tubes with no electronic contacts that one can pick up for less than $10. When I'm doing macro work I'm more likely to be using legacy lenses and manual focus anyway.
     
  6. ckrueger

    ckrueger Mu-43 Veteran

    304
    Jul 16, 2011
    Cool, so they're finally generally available in the US! I need to wait to hear about the electrical problems that were reported here earlier, but these are on my list for sure.

    DeeJay, you should give the system macro lenses a shot before you commit to a manual macro lens. AF is surprisingly good on M43 at macro range. Much better than it ever was with DSLRs. My 45/2.8 could stand to have a near-focus-only limiter, but even without it I get a very good hit rate with AF even down to 1:2. Accuracy is excellent, and the lens doesn't hunt very often so long as you give it a nice high contrast edge to chew on.
     
  7. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Keith
    For me, it really comes down to a matter of budget. $700 for the P45/2.8 macro plus $180 for the Kenko tubes is simply way more than I wish to plunk down for something that I'm simply not going to use that often; especially when I can put together a similar kit (minus autofocus) for around $100 using legacy glass.
     
  8. chlau

    chlau Mu-43 Regular

    65
    May 13, 2011
    Only on some of the lenses but these are also the most important ones. Every unit in the store had the same problems as were the units in another nearby store. However Kenko's list suggests they tested them stacked and they worked so it is possible that this problem is only found in the initial batches shipped.
     
  9. Sammyboy

    Sammyboy m43 Pro

    Oct 26, 2010
    Steeler Country
    Is this your personal experience or "hear-say" ?
    I find it hard to believe these tubes don't work when stacked, after all, they perform only two functions:
    1. Connect the electric circuit between the lens and the camera. If you look at the contacts on the lens and camera, they are rather large in size, large enough to make up for any tolerance discrepancies between the mating mounts.
    2. Add extension to provide magnification. When adding extension, there will be a loss of light hitting the sensor and a reduced and shortened focusing range. While the loss of light wouldn't be enough to prevent metering in a store room situation, the reduced focus range with both tube attached could create focus problems with short focal length lenses.
     
  10. chlau

    chlau Mu-43 Regular

    65
    May 13, 2011
    This was the issue I was having with my Kenko tubes which when stacked, worked selectively with my lenses. Crucially they didn't work on my 45/2.8. I only tested them on a 20/1.7 which I had with me when I was at the store in Singapore. I've since had them checked out and replaced but the problem is still there. The store has since contacted Kenko but I've not heard back from them yet. It might be a problem that's associated with this shipment so if anyone had a fully working set please let me know.
     
  11. Spuff

    Spuff Mu-43 Top Veteran

    652
    Dec 5, 2010
    Berkshire, UK.
    Compatibility chart:
    http://www.kenkoglobal.com/pdf/CompatibilityList_DG_EX-TUBE_ForML.pdf

    Officially they can't be stacked on the 20mm. And you need to be in a zoomed position on the 14-42 - but I guess you would be anyway.
     
    • Like Like x 1
  12. ckrueger

    ckrueger Mu-43 Veteran

    304
    Jul 16, 2011
    Understood. The 45/2.8 is overpriced IMHO, and if macro wasn't one of the primary things I shoot I would still be using my 35/3.5 (which is a very economical way to macro on M43, by the way!).
     
  13. Grinch

    Grinch Mu-43 Top Veteran

    813
    Jan 9, 2011
    Canada
    Could the issue with stacking be a loss of voltage due to increased resistance, hence not enough flow of current. I'm just surmising, but in my mind seems logical. I think I'd be hesitant, as it seems costly compared to my Minolta 55 3.5 with 1:1 adapter, and I can't see needing autofocus for macro. Just my opinion which amounts to squat, maybe an expert will correct me if I'm out of line.
     
  14. Wasabi Bob

    Wasabi Bob Mu-43 Top Veteran

    My experience

    I've had the Kenko extension tubes for a few weeks. I can verify that with certain lens, you cannot stack them. Ironically, one of the lens that cannot be stacked is the 45mm macro lens. Either the 10mm or 16mm individually work just fine. I had the problem with a GH2 and GX1. With the help of my local dealer we also verified the problem using two Olympus models.

    My set was sent back to Kenko's distributor in CA. They sent a replacement and stated that they are talking with the folks in Japan, but there is a possibility that it may not be possible. They also confirmed that it's definitely not a camera problem.

    I would prefer to be able to use both (together), but the 16mm by itself works great.
     
    • Like Like x 1
  15. RevBob

    RevBob Super Moderator

    Jun 4, 2011
    NorthWestern PA
    Bob
    This makes sense and would also explain why the company admits that it is probably not a camera problem but a problem with the extension tubes. Could be pretty much impossible to overcome if this is the case.
     
  16. oldsweng

    oldsweng Mu-43 Regular

    60
    Apr 21, 2011
    Oregon
    It could also be a signal integrity issue. If the signal is distorted then the rising and/or falling edges of the signal could be slowed such that the receiving end does not detect the signal transition. The reason some lenses may not work may have to do with the electronics transmitting the signal back to the body have minimal current drive capabilities and the extra distance distorts the signal. The lenses which work with the tubes may have more current drive capability and better impedance matching to maximize signal integrity.

    I realize this description may have made your eyes glaze over so I'll but it more simply. Lenses which don't work with the tubes probably just meet :43: specs for communications with the camera.

    These are just my thoughts as an Electronics Engineer with 40 years experience. I could be totally wrong and Kenko screwed up their design. :redface:
     
    • Like Like x 1
  17. Wasabi Bob

    Wasabi Bob Mu-43 Top Veteran

    Not a deal breaker

    The official Micro FourThird spec allows for only one "active device" in series with the lens. Each extension does include a signal conditioning circuit, so I suspect the "double conditioning" may be a contributing factor. As was previously mentioned, when both extensions are used together the digital data for some lens is most likely right on the edge of acceptable and non-acceptable.

    For me, it's disappointing but definitely not a deal breaker.
     
    • Like Like x 2
  18. oldsweng

    oldsweng Mu-43 Regular

    60
    Apr 21, 2011
    Oregon
    Thanks for this clarification! Is the Micro Four Thirds spec available to the public? All I could find was a summary of the specification.
     
  19. haakor

    haakor Mu-43 Rookie

    11
    Feb 27, 2011
    Vancouver
    Lens comparisons?

    If someone has the time and inclination I would be very keen to see a comparison on the 14-140 and 100-300 Panasonic lenses. If possible a set of photos of an common object like an AA battery with the regular lens, short tube, long tube and both linked.

    I am quite interested in these and am just curious to see how much I can leverage my existing gear compared to the new and upcoming Oly macro lens.

    Thanks to whoever has the time...
     
  20. Sammyboy

    Sammyboy m43 Pro

    Oct 26, 2010
    Steeler Country
    Actually I'm puzzled why folks are so "hepped-up" over these extension tubes. Personally, I prefer a couple of achromat close-up lenses of various diopter strengths in a large filter size so they can be adapted and used on various lenses, including legacy glass. There's no light loss with achromats as there is with extension tubes, and you certainly don't have the "communication problem" these tubes are exhibiting. Achromats and extension tubes alike, do not allow focus at infinity, so one has no advantage over the other. Don't get me wrong, I do use extension tubes and a bellows quite often, but only with very specialized lenses that require a long register just to be mounted, or with extension of 65mm or more. If you decide macro isn't your bag, I believe the achromats would be easier to sell, as they are not dependent upon a specific format.