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Thread: EF-s 10-18mm f4-5.6 Zoom

  1. #1

    Default EF-s 10-18mm f4-5.6 Zoom

    Picked one of these up second hand from my local CEX recently.

    One thing I have noticed is that when zooming the lens loses focus - is this typical? I did read somewhere that because the focus mechanism is electronic there is no mechanical connection to the focus ring. Could this be why the lens does not hold focus - no mechanical connection between the focus and zoom mechanisms?
    Nigel

    You may know me from Another Place....

    The new ElSid Photogallery...

    Equipment: Far too much to list - including lots of Nikon...

  2. #2
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    Default Re: EF-s 10-18mm f4-5.6 Zoom

    Surely the focusing happens AFTER zooming? ie when you press the shutter button.

  3. #3

    Default Re: EF-s 10-18mm f4-5.6 Zoom

    Oh it focuses OK but if you zoom across the range after focusing it goes out of focus far more than my 10-20 Sigma does - the Sigma barely drifts while the Canon clearly goes soft and fuzzy. What I'm trying to work out is if this is normal behaviour for this lens...
    Nigel

    You may know me from Another Place....

    The new ElSid Photogallery...

    Equipment: Far too much to list - including lots of Nikon...

  4. #4
    Member Farider's Avatar
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    Default Re: EF-s 10-18mm f4-5.6 Zoom

    Iíve just checked mine on my 80D using live view on 10X magnification and the focus is maintained when you from 10mm to 18mm and back. It does not matter at which end of the zoom range you initially focus. I have checked this at both minimum distance and intermediate and the results are the same. ( I use back button focusing by the way)

    You may have a problem so it might be worth getting back to where you brought it to check it against a new one
    Ian

  5. #5

    Default Re: EF-s 10-18mm f4-5.6 Zoom

    A quick update...

    Playing around on Saturday afternoon (while in Bognor) I got to the bottom this and it's not the lens that's the problem but the state of the camera...

    If the camera is in standby mode or otherwise inactive then zooming the lens causes the lens to defocus but as soon as any button is touched and the camera wakes up the lens immediately refocuses correctly. If the camera is activated then then zooming does not cause any defocus issues.

    It's not just this STM lens either, I checked my 17-85 USM and it does exactly the same. It would appear that with the camera on standby there's no power to the lens but as soon as the power comes back the focus activates and resets itself.

    Considering I've been using EOS cameras for the best part of 20 years I'm amazed I've never noticed this before...
    Nigel

    You may know me from Another Place....

    The new ElSid Photogallery...

    Equipment: Far too much to list - including lots of Nikon...

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