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

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: [Leica] OT auto focus tip
From: telyt at (Douglas Herr)
Date: Tue Jul 25 00:36:13 2006
References: <> <> <>

On Jul 24, 2006, at 5:08 PM, Adam Bridge wrote:

> Well I can't move the autofocus position to ANY location on the screen
> but I have a wide variety on the 1Ds Mk II, Doug, that would put the
> focus where you would be likely to have them. It does work. Or can
> manually focus and use focus confirmation to mark the place where the
> camera finds the image to be in focus.
> Adam

OK... let me see if I can explain this more clearly.

I want to be able to focus quickly, accurately, and simultaneously 
anywhere and everywhere on the viewscreen.  My subjects are very 
active, even when they appear to be sitting still.  They might yawn, 
turn their head, shift weight from one foot to the other all in 
fractions of a second, each time shifting the plane of best focus.  The 
eye could be anywhere, at any time so I cannot pick a particular focus 
point to watch.  For example, are there any focus points at this 
pheasant's eye?  Recall that this is exactly as I saw it in the 
viewfinder, no cropping:

In addition, I often watch multiple points or regions for optimum 
focus, in this case, eye, back, and tail:

and with this bird, near eye, beak, 'ear' tufts, shoulder:

beak, eye, neck:

eye, chest, shoulder, fruit, toes:

eye, beak, neck, wing, particularly as it twists, dips and flicks 
feathers while preening:

from tip of beak to tip of tail:

beak, eye, neck, back:

eye, nose, paw, and as much of the seed pod as possible:

eye, nose, beak and shoulder in lower right corner:

eye, beak, neck, back as much of wings and tail as possible:

These areas aren't all in focus by accident; I'm watching all of these 
points simultaneously and shifting my position or waiting until the 
bird lines itself up with my focus plane.  When everything comes 
together my shutter finger has to respond immediately; the fraction of 
a second used shifting the view for optimum composition is enough time 
for all sorts of stuff to shift out of the focus plane, and to watch 
this many regions simultaneously I'd rather use a viewscreen that shows 
me clearly and unambiguously where stuff is in or out of focus, all 
over the viewscreen all at once.  Let me be clear about this: these 
areas aren't all in focus by accident.

Perhaps my needs are more specialized than the majority of camera 
users' needs, but there is no AF camera yet made that has focus points 
covering the entire viewscreen nor is there an AF camera yet made that 
can have enough simultaneous active focus points nor is there an AF 
camera yet made that includes the optimizing algorithm in my brain that 
can determine which of several active focus points are the most 
critical ones, and an AF camera in manual mode with its compromised 
viewscreen is not optimum for the kind of photos I want to make.

Doug Herr
Birdman of Sacramento

Replies: Reply from jbm at (Jeff Moore) ([Leica] OT auto focus tip)
Reply from imagist3 at (Lottermoser George) ([Leica] OT auto focus tip)
In reply to: Message from roy at (Roy Feldman) ([Leica] OT auto focus tip)
Message from telyt at (Douglas Herr) ([Leica] OT auto focus tip)
Message from abridge at (Adam Bridge) ([Leica] OT auto focus tip)