Unsharp pictures with 7D and EFS 17-55mm, F2,8. Peter, Copenhagen

Started Nov 1, 2012 | Discussions thread
rickpoole
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Re: Unsharp pictures with 7D and EFS 17-55mm, F2,8. Peter, Copenhagen
In reply to petwil01, Nov 1, 2012

Peter,

As others have said at f2.8 the DOF is very shallow...at the closer distances you were shooting the DOF was probably only a few inches.  Focusing and recomposing with this shallow a DOF can definitely make the focus appear off as will as a subject that moves just a few inches between focusing and shooting.  Canon's servo focus tries to predict where the subject will be when the shutter fires and adjusts accordingly.  But it is not perfect, a subject that changes direction can trick it into making the wrong adjustment, i.e., kids, pets, insects, birds, etc.  Stopping down to f5.6 to f8 will double to triple your DOF making focusing errors much less apparent.

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Canon EOS 7D Canon EF-S 17-55mm f/2.8 IS USM Canon EF 100-400mm f/4.5-5.6L IS USM Canon EF 100mm f/2.8L Macro IS USM Canon EF 70-200mm f/4L IS USM +7 more
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