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Thread: 70-200mm IS USM v 100-400mm

  1. #1

    70-200mm IS USM v 100-400mm

    I've read a similar thread on this topic before, but my question is a bit different.

    I'm trying to decide between the two, however, I wouldn't be using a 2x teleconverter.

    I have a 50D now (1.6x) and am planning on getting the 1.4x teleconverter. Now, correct me if I'm mistaken but that would yield the same results as if I was using a full-framed camera with a 2x converter, right?

    Anyway, I haven't seen any comparisons with the 1.4x converter, and I'm not sure how much sharpness it will lose... Does anyone have any insight on this?

  2. #2

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    Re: 70-200mm IS USM v 100-400mm

    In many respects, it depends what you will be doing with the lens.

    The 70-200 is an excellent general purpose zoom while the 100-400 is favoured with wildlife photographers who frequently use it with a converter for more reach.

    Both lenses should work reasonably well with a 1.4x converter; subject to the usual warnings about slight loss of light etc.

  3. #3

    Re: 70-200mm IS USM v 100-400mm

    Do you happen to know by chance how significant the loss of sharpness is with the 1.4x converter?

    Now I'm having trouble deciding which lens to get; both seem to be great. The 70-200 for sports / walk around zoom, the 100-400 for wildlife.

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    Re: 70-200mm IS USM v 100-400mm

    Quote Originally Posted by Fallacy View Post
    Do you happen to know by chance how significant the loss of sharpness is with the 1.4x converter?

    Now I'm having trouble deciding which lens to get; both seem to be great. The 70-200 for sports / walk around zoom, the 100-400 for wildlife.
    Wide open the 100-400 is marginally sharper than the 70-200 with a 1.4x TC, but once you stop them both down into the F5.6 / F8 range there's nothing between them.

    Also, don't let a minor drop-off in sharpness concern you too much - in my experience around 90% of lack of sharpness that I see in images is due to incorrect (and often non-existant) sharpening, and only around 10% due to the lens. In practice you have to be a little more precise when sharpening images with TCs attached, but it's no big deal.

    We discussed it recently - have a read of this thread if you have time.

    Also, you can read a bit about sharpening here.

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    Re: 70-200mm IS USM v 100-400mm

    Quote Originally Posted by Geoff F View Post
    Both lenses should work reasonably well with a 1.4x converter; subject to the usual warnings about slight loss of light etc.
    Keep in mind though that you'll probably lose autofucus with the 100-400 + 1.4xTC at the 400mm (F5.6) end on a 50D. (F5.6 + 1 Stop loss for 1.4x TC = F8 which will only AF on 1D series cameras).

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