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Canon 100-400 f5.6L IS + Canon 1.4x Converter

Discussion in 'Photography Forums' started by rcmarple, Oct 7, 2005.

  1. rcmarple

    rcmarple
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    I'm an idiot.

    Took delivery of a 1.4x converter to go with my shiny new £1000+ lens and guess what? I didn't do my research properly and missed the slight hitch of AF not working unless your lens is f4 or lower.

    BUMMER.

    Be warned guys and gals... :eek:
     
  2. mr jones

    mr jones
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    i only found that out after johndm posted a huge load of info about how it works


    luckily i only plan on getting the 70-200f2.8L which is within limits



    i thought it was above f5.8 on the lens, not f4
     
  3. rcmarple

    rcmarple
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    "The effective aperture of the lens is increased by one stop. Autofocusing does not operate if the effective maximum aperture is greater than f/5.6"

    EFFECTIVE is the key word here which I missed. Effective means the aperture AFTER you fit the converter. On the 1.4, you lose one stop and on the 2x, you lose two stops.

    So on the 100-400 f5.6L lens, the effective aperture is f.8 = no working AF.

    STILL A BUMMER. :mad:
     
  4. Pink Fairy

    Pink Fairy
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    There are ways to get around this, notably taping over some of the pins of the tc to fool the camera.. but you'll get sluggish & unreliable AF in all but very good light. All in all you're better off without a tc on this lens.
     
  5. HCking

    HCking
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    Just for info the AF still works on 1 series cameras upto f8.
     
  6. Johndm

    Johndm
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    Hey....we all make mistakes sometimes.... :suicide: The info is hard to digest when your all keyed up to buy.... :rotfl:

    I was VERY strong today...while dragging my missus around Currys, she pointed at a LG 32" LCD telly, and uttered...'like that...its got a nice black surround....buy it'

    I refused to get my plastic out...noted the model number, and am about to start gathering info on why the 42" Plasma is just so much better... :devil: :devil:

    :hiya:
     
  7. BocheB

    BocheB
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    In my experience the AF is totally unreliable using this method in even very bright light - it's totally hopeless. Image quality is also no great shakes when you add a TC to the 100-400.
     

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