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