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Thread: Extension Tubes Revisited

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    Default Extension Tubes Revisited

    I read Anita’s thread with some interest of adding an extension tube(s) to my system. My research turned up a Kenko C-AF Uniplus 25 and the Kenko DG set with a 12, 20 and 36 tube. I’m shooting Nikon with both D & G type lenses and a D300 and D3s. Does anyone have any preferences or feedback? Your comments, as always, are appreciated.

  2. #2
    Roman Kurywczak
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    Hey Gene,
    I have the Kenko tube set (for Canon) and my older version is metal......if they went to plastic.....avoid because of the flex and possible failure from weight. I will also be interested in the feedback.

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    Quote Originally Posted by Roman Kurywczak View Post
    Hey Gene,
    I have the Kenko tube set (for Canon) and my older version is metal......if they went to plastic.....avoid because of the flex and possible failure from weight. I will also be interested in the feedback.
    I would not simply suggest "avoid". I use Kenko and so do many, I believe. At the end of the day, it all depends on how you use them. I have no problem with them so far.

  4. #4
    Roman Kurywczak
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    No way I put plastic with a 500mm! I want a tube that works with all!

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    I have both the Uniplus tube and the DG set and they work fine for Nikon and they do autofocus. I believe it would require a tremendous amount of force to cause flex or failure of the tube, but then I've never stressed mine all that much.

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    If you stacked all three on a 500mm or a 70-200mm there'd be lots of potential stress. With both of those lenses you're going to be holding the camera body and the lens at the same time, but there can be a lot of torque when lifting or zooming. I don't know why you'd go with plastic if metal were available. If you want to save money AND you use only one at a time AND only use it on lenses shorter than 100mm, then maybe ok.

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    I have to agree, stacking them would be a concern. Nikon users don't have many choices for extension tubes that allow autofocus.

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    Boy, I was hoping this thread would help making a decision easier. Thanks for all your input!

  9. #9
    Allen Johnson
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    Well I tried the Canon 25mm extension tube and am not to happy. I got it sent from bhphoto and it arrived on Friday. I took it to the Wild Animal Park and tried it out. It initially worked for a few shots but then stopped focusing... I tried various combinations. With and with out my 1.4 converter. I tried the 2 lenses 800mm and 300 on my Mark IV. I then tried the 25mm on my 5D Mark2. Any other suggestions ??

    Thanks
    Allen

  10. #10
    Lance Peters
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    Use the Kenko with Nikon - no problems at all - use em stacked - no problems - AF as well.

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    Quote Originally Posted by Allen Johnson View Post
    Well I tried the Canon 25mm extension tube and am not to happy. I got it sent from bhphoto and it arrived on Friday. I took it to the Wild Animal Park and tried it out. It initially worked for a few shots but then stopped focusing... I tried various combinations. With and with out my 1.4 converter. I tried the 2 lenses 800mm and 300 on my Mark IV. I then tried the 25mm on my 5D Mark2. Any other suggestions ??

    Thanks
    Allen
    I know it is a basic question but were you within the working range Allen ? remember with Extension tubes the maximum focussing distance is severely restricted. I was doing some test's the other day with my 300/2.8 and the working distance with a 21mm extension tube was 1.75-5.2 mtrs. With a 31mm tube the maximum focus distance is down to 3.5 mtrs.
    I would guess that a 25mm tube would give a max focus distance of around 4 mtrs so anything over this and you would not get AF. Just a thought!

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    Quote Originally Posted by Allen Johnson View Post
    Well I tried the Canon 25mm extension tube and am not to happy. I got it sent from bhphoto and it arrived on Friday. I took it to the Wild Animal Park and tried it out. It initially worked for a few shots but then stopped focusing... I tried various combinations. With and with out my 1.4 converter. I tried the 2 lenses 800mm and 300 on my Mark IV. I then tried the 25mm on my 5D Mark2. Any other suggestions ??
    Move forward toward a subject until you get focus. With my 500mm f/4L IS the maximum focus difference is around 10-meters. If you're operating with the ranges to be expected for macro photography, with long lenses, then there's something wrong with you ET and it needs to be replaced.

    With an 800mm and a 1.4TC and the ET, a bee will pretty well fill your viewfinder, particularly on a crop-sensor.

  13. #13
    Allen Johnson
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    I even tried to use Manual Focus and I could not get anything to come into focus at any distance :(

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    Quote Originally Posted by Allen Johnson View Post
    I even tried to use Manual Focus and I could not get anything to come into focus at any distance :(
    That is very strange Allen as Extension tubes have no glass so if you are within the working distance I cannot see how manual focussing can possible fail. Even if the AF side was faulty in the tubes it should still manually focus (again providing you are within the focussing range).

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