RE: PLANE OF SHARP FOCUS

Gary -

> ...why is the plane of sharp focus verticle when the
> camera back is not verticle...?

Are you sure the back (and front) of the camera was not tilted back to the
vertical after the rail (or bed) was pointed down into the subject? This
would be indirect displacement to get front fall (or rear rise) from a
camera that didn't support it.

Were Avedon's images so lacking in depth of field that you could really see
the exact plane of focus? With adequate depth of field the whole subject
could be in focus even without tilting the back and front back to vertical
after pointing the bed down. If there really is a clearly visible vertical
plane of focus, I'd pretty much agree with Robert that it couldn't be done
with both front and rear standard normal to the lens axis, and the camera
set-ups aren't quite real.

One last geometrical note: If the rear was normal to the lens axis, but the
front was tilted, you could get a vertical plane of focus, and a camera that
looks pretty much like it's pointed right down into the subject--you might
not notice the front tilt. But, with the back effectively tilted forward,
perspective would become distorted, and (in this case) the bottom of the
torso would look oddly smaller than the head would suggest. This might be
useful for slimming a subject's waist, but I haven't tried it.

> ...what is the advantage of the camera position
> he used?

Compositionally, this (camera above, front fall) puts the viewer above the
subject. Sure, the subject is centered in the frame, but your point of view
will show more hair, less neck, and a slightly foreshortened torso. If the
subject has an unflattering neck or double-chin, or if you want to show off
the subject's beautiful hair, or give the subject more mass, this can help.

Thinking deeper, the viewer will pick up the physical cues that they are
"above" the subject...and some would say this also puts the subject in a
psychologically diminished position, also. You could go further, to motive,
and wonder why the photographer might want to convey that relationship to
the viewer. Is it intentional? I bet some thought went into that, if the
photographer went to all that trouble to get above the subject.

Inversely, you can also put your subject in a heroic stance by putting the
lens axis at the subject's crotch or knees, and using front rise to center
the head and torso in the frame. Now the subject is above the viewer.
Think of old propaganda illustrations (pick your country) of children in
uniform looking up at their nation's flag, from a vantage point practically
on the ground.

        - Dan Haygood

P.S. Sorry to reply to Robert's message, but I didn't have your original.

-----Original Message-----
From: Richard Knoppow [mailto:dickburk@ix.netcom.com]
Sent: Saturday, December 24, 2005 1:30 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: PLANE OF SHARP FOCUS

----- Original Message -----
From: "Gary Shank" <gshank@flash.net>
To: <alt-photo-process-l@usask.ca>
Sent: Saturday, December 24, 2005 8:08 AM
Subject: PLANE OF SHARP FOCUS

> The Amon Carter Museum is currently showing a collection
> of Richard
> Avedon portraits. They also have photos which show the
> subject,
> background, & camera locations for these portraits. The
> portraits were
> taken outdoors using natural light. The camera he used
> was a 8x10
> field camera which was located about 12 feet from the
> subject. The
> camera height was about the same as the head of the
> subject and the
> camera bed was angled down so the lens axis was in line
> with the chest
> of the subject. The back of the camera was normal to the
> lens axis so
> it was tilted forward relative to the ground plane. The
> photographer
> had to stand on a box to view the ground glass. By
> examining the 40 x
> 50 in. portraits, the plane of focus is vertical and
> extends from the
> eyes to the belt buckle. The portraits are not cropped
> and they extend
> from the top of the head to a few inches below the belt.
> My question is
> why is the plane of sharp focus verticle when the camera
> back is not
> verticle and what is the advantage of the camera position
> he used?
>
> Gary Shank
>
   Since neither the lens or back appears to have been
tilted i.e., they were both perpendicular to the bed, and
the bed was apparently tilted with regard to the subject. If
this is so, the object plane (plane of sharp focus) would
also have been parallel to the camera and diagonal to the
subject.
 my only guess is that the photos of the set-up do not
represent the actual conditions of the photo.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com