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Focus issue with Canon 100D/SL1

Started Oct 11, 2015 | Discussions
Sean Lovegrove New Member • Posts: 1
Focus issue with Canon 100D/SL1

Hi all, I have a Canon 450D which I use with a Sigma 150mm macro with single point autofocus- no problems. I am trying the lens on a Canon 100D. Press to focus, nice crisp view in the view finder and the familiar 'beep' - but after a second or two, the image starts to blur. Press again, focuses perfectly, then drifts again - any ideas? Thanks

Canon EOS 450D (EOS Rebel XSi / EOS Kiss X2) Canon EOS Rebel SL1 (EOS 100D)
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ThrillaMozilla Veteran Member • Posts: 7,681
Re: Focus issue with Canon 100D/SL1

Read the manual.  There are MANY focus options.  You may have set it to follow focus.  Set it to single shot focusing.  If in doubt, set the camera back to factory defaults.

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WilbaW
WilbaW Forum Pro • Posts: 11,643
Re: Focus issue with Canon 100D/SL1

ThrillaMozilla wrote:

Read the manual. There are MANY focus options. You may have set it to follow focus.

Do you mean one of modes that applies in Live View, or AI Servo?

Set it to single shot focusing.

He's getting a confirmed focus through the viewfinder, so that's not the case.

If in doubt, set the camera back to factory defaults.

Worth a try, but I can't think of any function that changes a confirmed focus except AI Focus.

Sean, what's your "AF Operation" set to? (Page 103 in the 100D manual.) One-Shot, AI Focus, or AI Servo?

When "the image starts to blur", is the focus ring on the lens turning? Does it stop when you release the shutter button?

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rjjr Forum Pro • Posts: 14,769
Re: Focus issue with Canon 100D/SL1

Sean Lovegrove wrote:

Hi all, I have a Canon 450D which I use with a Sigma 150mm macro with single point autofocus- no problems. I am trying the lens on a Canon 100D. Press to focus, nice crisp view in the view finder and the familiar 'beep' - but after a second or two, the image starts to blur. Press again, focuses perfectly, then drifts again - any ideas? Thanks

Sorry for asking obvious questions but is it mounted on a tripod? If handheld, could you be moving?

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