Stacking EF 1.4x and EF 2x

Discussion in '35mm Cameras' started by Nick J, May 22, 2004.

  1. Nick J

    Nick J Guest

    ok no comments on the inevitable optical degradation but...

    Does anybody know if this is even mechanically possible or do the
    protruding front elements prevent this?

    I have the EF1.4x which I use in conjunction with my 135mm

    I don't wish to shoot a lot of long reach tele stuff so I'm not prepared
    to carry substantial extra weight or splash the cash however...

    every know and then there is a time you just need that length. On a 300D
    that would be a '35mm equiv' 600 f/5.6. How bad can an L prime attached
    to two Canon teleconvertors be ;-)

    Nick J, May 22, 2004
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  2. Nick J

    Bill Hilton Guest

    From: Nick J
    With a REALLY good lens the results are surprisingly good ... I've got a
    red-tail hawk shot I could show you with a 500 f/4 L IS and stacked t/c's ...
    with a bad lens don't even bother though.
    With the new 2x (the one that came out a couple years ago, marked "2x II") you
    can mate them without a problem since it has a recessed rear element ... so
    it's body, 1.4x, 2x II, lens.

    With the earlier 2x you can't do it direct because the rear element is almost
    flush with the mount, but you CAN work around this by adding the 12 mm
    extension tube as a spacer. The downside of this is you lose infinity focus.

    Either way the body won't know the t/c's are stacked so at wide open it will
    indicate the wrong aperture, off by one stop, so be sure to check for this. In
    other words, with my 500 f/4 and stacked t/c's I've got 1,400 mm at f/11 but
    the body only knows the 2x is there so it will let you shoot at a reading of
    f/8 in Av mode even though it's really f/11 and the shots will be underexposed.
    So make sure you're at f/11 or smaller to have it meter correctly.
    If this is the "L" lens you'll probably be happy enough with the results.
    Yep, even with a 500 mm and a 2x t/c ...
    Here are some sites with good images taken with stacked t/c's from well-known
    nature photographers ... (click the 'workshop' link, then 'Preparation: Sharp
    Photographs" and then down to charts 7 and 8 for Fritz's comments on the
    quality one can expect with stacked t/c's and excellent lenses).

    Bill Hilton, May 22, 2004
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  3. <snip>

    I just took a look at my 2x. It's not marked 2x II, but the rear element
    seems recessed at least as much as the front is extended. I suppose I
    should measure that, but it isn't anywhere near flush with the mount. Were
    there more than just two versions of Canon's white doubler? I'd love to be
    able to stack extenders, and would even get a 1.4 if it would work with my
    2x. Not sure what sort of quality I'd get from the 100-400 zoom, but....

    Any ideas here?


    Bill Tallman
    William D. Tallman, May 22, 2004
  4. Nick J

    Nick J Guest

    great, that's what I wanted to hear
    sounds a bit of a pain - most of the time I need the length I'm at infinity.
    yup it's the wonderful 135mm f/2L. It's rarely the camera that's the
    limiting facor in my photography but I can safely say that this is a
    better lens than I will *ever* be photographer.
    lol, that's more like a telescope :)
    some great looking shots there

    Nick J, May 22, 2004
  5. Nick J

    Bill Hilton Guest

    With the new 2x (the one that came out a couple years ago, marked "2x II")
    Hi Bill,

    The new one definitely says "Extender EF 2x II" on it so you probably don't
    have that version.
    I used to have the older one and as I recall the back element was not recessed
    very much. There's no way the 1.4x would mate to it without touching the
    glass. You need about half an inch.
    I don't think so ...

    I think the 100-400 is pretty soft with the 2x (though I confess I've only shot
    a couple frames with it since I already have a 500 f/4) and I'd venture it's
    very marginal with stacked t/c's ... you're talking about 1,120 mm @ f/16.

    Here's a chart that relies on Canon's MTF info and says the 100-400 is pretty
    good with the 2x, but it also says it's better than the 300 f/4 L with a 2x,
    which I find pretty hard to comprehend. Drop another notch when you stack
    t/c's ...
    I would try to borrow or rent a 1.4x for testing since I think you're
    approaching the limits of acceptable image quality when you stack two t/c's on
    the 100-400, but it's worth checking for yourself first hand.

    Bill Hilton, May 22, 2004
  6. Nick J

    Bill Hilton Guest

    One more page of examples of the type image you can expect with stacked 1.4x
    and 2x Canon t/c's on their best lenses ... -> the 'workshop 2' link -> 'converter -
    turn up the size' link and scroll down to 'A new auto-focus lens: 11.0/1400 mm'
    .... "The eye of a Cheetah' shot is pretty cool, considering it was taken from a
    window mount with asa 100 speed film.

    Bill Hilton, May 22, 2004
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