Kenko 3x teleconverter and Canon bodies and lenses

Discussion in 'Canon' started by JC Dill, Jun 12, 2007.

  1. JC Dill

    JC Dill Guest

    Does anyone here have a Kenko 3x teleconverter?

    http://www.adorama.com/KN3XPEOS.html

    I would be pairing it with my Canon 70-200 F2.8 L IS USM lens, on a
    Canon 1DMII body. I'd be shooting in bright sun (horse show
    photography) and F8 works fine in that setting. I haven't found any
    online reviews of this TC. I know the Canon 2x TC is often said to
    result in soft images and I'd love some info on this Kenko 3x.

    Thanks!

    jc
     
    JC Dill, Jun 12, 2007
    #1
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  2. JC Dill

    Frank Arthur Guest

    If you enlarge the image 3x it's size you will get superior results
    to the 3x converter.
     
    Frank Arthur, Jun 13, 2007
    #2
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  3. JC Dill

    Mark B. Guest

    I've never read anything good about a 3x converter, regardless of the lens
    it's used on.

    Mark
     
    Mark B., Jun 13, 2007
    #3
  4. JC Dill

    RichA Guest

    I doubt that. Even if the resultant image was soft, you are still
    likely to get more detail from the teleconverter and lens than the
    lens itself. If not, the teleconverter is trash, or the lens is
    trash. A high-end 200mm lens should support a doubling or even a
    tripling of it's effective mm's and the image shouldn't break down.
    But as for the ultimate quality, you'd have to find out if resolution
    is more important to you than sharpness since they are NOT always one
    and the same.
     
    RichA, Jun 13, 2007
    #4
  5. JC Dill

    Frank Arthur Guest

    I am sure you never personally used a 3x converter on any lens-high
    end or not and you do not know if the image would "break down" if the
    3x converter was used..
     
    Frank Arthur, Jun 13, 2007
    #5
  6. Just make sure you can return it ...
    I guess that's because even 2x converters are borderline (you
    need a really good one and a stellar lens to pull that off)
    and 3x are toys. But do try it out, and compare with
    upsampling from w/o a converter, 1.4x converter and 2x
    converter.

    Or bite into the sour apple and get yourself a Canon 400mm USM
    (no IS) f/5.6 + 1.4x converter. That will give you a similar
    reach and a *much* better quality ...

    -Wolfgang
     
    Wolfgang Weisselberg, Jun 13, 2007
    #6
  7. JC Dill

    RichA Guest

    I don't doubt that a 3x converter would probably do that, as mfgs
    aren't going to invest huge amounts of money to MAKE a good 3x
    converter because of the speed reduction it places on any lens it is
    used with. But using a converter is no different than "digiscoping"
    where an intermediary lens (in that case, a spotting scope eyepiece)
    is placed between the main lens and the camera to increase effective
    focal length. The only reason it wouldn't produce more detail with
    increased magnification would be if one of the optical components was
    flawed.
     
    RichA, Jun 13, 2007
    #7
  8. I use stacked 1.4x and 2x TCs on my 500 f/4 L IS.
    On 1D cameras, you still get autofocus too!
    At that magnification, the main issue regarding sharpness
    is camera shake, although in perfect conditions the image
    is slightly softer than with a single TC. But the combo
    still resolves more subject detail.

    Examples
    http://www.clarkvision.com/galleries/gallery.bear/web/brown_bear.c09.08.2004.JZ3F1965.b-700.html

    http://www.clarkvision.com/galleries/gallery.bird/web/c12.16.2002.IMG_1365.hawk.b-600.html

    http://www.clarkvision.com/astro/saturn.03.02.2004

    Roger
     
    Roger N. Clark (change username to rnclark), Jun 14, 2007
    #8
  9. JC Dill

    John Sheehy Guest

    Yes, with a poor lens and/or converter, or bad technique.


    --
     
    John Sheehy, Jun 15, 2007
    #9
  10. JC Dill

    John Sheehy Guest

    Perhaps, but how many people commenting actually understand what a TC does
    and have realistic expectations from one?

    A 3x, even if made perfect by some supernatural miracle, is going to result
    in lower pixel-to-pixel contrast, and how much depends on the quality of
    the main lens.

    Some people seem to think that they're going to get the same image
    sharpness as the main lens, with a narrower FOV.

    --
     
    John Sheehy, Jun 15, 2007
    #10
  11. I just bought one myself a few days ago (from b&h, mainly because they have
    it in black vs adorama's white).
    Took some rough random test shots. Haven't had a chance to try it outdoors
    in broad daylight yet:

    http://www.pbase.com/mrdimitri/kenko3xpro_tests

    I think it performed much like described in a user review (at b&h web site)
    and I don't think it did that bad at all, considering it's a 3x and all.
    It even autofocused at f2.8 or larger (as prescribed, otherwise I had to
    focus manually) and metering did not get affected either.
    The shots I uploaded were the ones taken with the 70-300mm f/4-5.6 IS and
    the 50mm f/1.8.
    I also took some shots with the 75-300mm III, but it was practically
    impossible to avoid the camera shake affect especially at the long end in
    the result of which the shots were virtually unusable and weren't worth
    uploading. The IS (on the 70-300mm f4-5.6 one) definitely did it's job -
    these (including the ones with the 50mm f1.8) were all taken hand held, no
    tripod.
    I think you can draw your own (at least some substantial ones) conclusions
    from here...

    Here's the one at B&H:
    http://www.bhphotovideo.com/c/product/411595-REG/Kenko_K30PRO300DGC_3x_PRO_300_DG.html

    DC
     
    Dimitri Cohen, Jun 15, 2007
    #11
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