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Old Apr 4, 2011, 10:43 AM   #1
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I've experienced a few cases recently where I've been shooting with the aperture wide open at f1.8 and wanted the subject off centre. If I focus and keep the subject centred it's sharp but if I lock the focus and move the camera it's soft. I think the slight rotation of the camera is altering the distance between the focal plane and subject too much when the dof is so shallow. Any tips on how to do this better other than manual focus or restricting myself to one of the 15 focus points my camera offers?
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Old Apr 4, 2011, 11:08 AM   #2
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Yep. Here's an article on the subject:

http://www.outbackphoto.com/workshop...y06/essay.html

Selecting the desired focus point is the probably best approach if you really need to shoot an off center subject with DOF that's very shallow.

You could try leaning a tad after locking focus to change focus distance (until you get it just right via practice with a given lens/subject type/subject distance).

P.S.

Behavior will probably vary by lens. But, usually the curve of the focus plane with a typical lens causes subjects closer to the camera to come into focus as you get further from the center of the frame. So, if you practice leaning back and forth a tad to get a better idea of it's behavior, you may improve focus accuracy when recomposing using wider apertures.
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Old Apr 4, 2011, 11:16 AM   #3
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Why do you think you must restrict yourself to one of the focus points? You can perform the same focus and shift action...you'll simply be doing it from a focus point that is much closer to the final placement of the subject.

I don't have that lens, but you should perform a test and focus on something at the outermost focus point to see if it's a focus problem or simply a softening characteristic of the lens.
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Old Apr 4, 2011, 12:30 PM   #4
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Thanks Jim, that describes exactly what I'm seeing.
Graystar, there is indeed some softening at the edges but the effect I'm seeing is more than that. Jim's link suggests using the other focus points and moving the camera less. Was easier on my fz38 though as I could set the focus point anywhere.
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Old Apr 5, 2011, 7:46 AM   #5
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BTW, if the subjects are human, you may want to try using using Live View with Face Detection. That feature not only tries to focus on faces, it tries to give better exposure accuracy to the faces in a scene, too.
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