Re: 3D quality in a lens?

[Paul Stenquist]

If you shoot a  foreground object with a long lens wide open, it 
separates from the background in such a way as to produce an apparent 
"3D" effect. Of course, as JCO points out, it's not really 3D. It's 
merely the eye recognizing a difference between a sharp foreground and 
an out-of-focus background. Lenses with nice bokeh, like the 77 
limited, do this quite effectively. With extremely long lenses, like my 
A-400/5.6, the effect is very easy to achieve. Here's an example:
http://www.photo.net/photodb/photo?photo_id=2875014
On Nov 11, 2004, at 10:33 PM, J. C. O'Connell wrote:

If you have ever done or seen any decent
3D photography you would know it's a really
dumb way to describe any 2D image. I wouldnt
read too much into it, or put too much trust
in the writers of just descriptions...
JCO
-----Original Message-----
From: Don Sanderson [mailto:[EMAIL PROTECTED]
Sent: Thursday, November 11, 2004 10:23 PM
To: PDML
Subject: 3D quality in a lens?
What is meant when a lens is described as having
a "great 3 dimensional quality"?
Or "it gives photos a 3 dimensional feel"?
I've heard this term used several times in describing
lenses, mostly WA's.
How does a lens lend a 3D quality to a photograph?
TIA
Don