D800, 85mm 1.4G and focus shifting.

Started May 15, 2012 | Discussions thread
mark kay
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Re: D800, 85mm 1.4G and focus shifting.
In reply to inasir1971, May 15, 2012

The other approach is to focus at the max aperture 1.4 or 1.8 and then change the aperture to what you really want to shoot at. You have to make sure the camera is set so that as you re-press the shutter button you are not refocusing.I guess you can set AF lock while you adjust the aperture.

inasir1971 wrote:

Hi JMacedo,

Focus shift is one of the issues with fast primes. Here is the focus shift pattern for the 50 1.4G and 50 1.8G (download the originals to see full vertical resolution).

Hopefully, there is a 'window' where all apertures will be in focus - this is usually going to mean adjusting your focus point further back when wide open. At wide apertures, focus shift is greater than increasing DOF, and at smaller apertures increasing DOF is greater than focus shift. After you fine tune your AF, you need to check if in focus from wide open to around f4, after that increasing DOF more than compensates for any focus shift effects...

Hope that helps...

EDIT: Focus shift moves the focus point backwards, away from camera, as lens is stopped down...

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