Archived posting to the Leica Users Group, 2006/07/25

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Subject: [Leica] OT auto focus tip
From: telyt at (Douglas Herr)
Date: Tue Jul 25 20:07:22 2006
References: <>

On Jul 25, 2006, at 8:37 AM, wrote:

> If it hasn't already been suggested, read Canon's white paper for more 
> info on using autofocus correctly.
> What others have said regarding the traditional focus-recompose 
> technique is not altogether incorrect. However, for close-up work and 
> shallow depth of focus, it's not the best.
> See pages 11 and 29 of the .pdf for more.
> By the way, when working in low light, the extra-sensitive, center 
> autofocus point is sometimes the only one that works. Ah, well.
> -Chris Lawson

In particular, Canon's white paper says:

"For optimum focusing performance with close subjects, we recommend 
avoiding the FLR technique. Instead, use an off center focusing point 
or focus manually."

(FLR is Focus-Lock-Recompose)

and later in the white paper:

"The closer the subject, the more critical accurate focusing becomes. 
One potential problem to avoid is camera or subject movement after 
focus lock. This can happen more easily than one might think... Even 
slight camera movement or subject movement after focus lock can result 
in soft images, particularly when shooting at wide apertures with 
narrow depth of field."

Doug Herr
Birdman of Sacramento

In reply to: Message from mcyclwritr at ( ([Leica] OT auto focus tip)