Question for the lens gurus...

[Bob Fowler]

Reading through Jay Allen's book "Pictorial and Soft Focus Lenses of the Past", I noticed that in the section on the Wollensak Veritar (pg 47) it says "The Portrait Veritar differs from an ordinary anastigmat lens in that as the lens is stopped down the depth of field increases only behind the point focused on."

Is that because of the placement of the iris? If so, is the iris closer to the front than normal or closer to the rear? Am I missing something else?

[Michael Gudzinowicz]

The Veritar relies on spherical aberration to produce the soft focus effect.
A fairly good example of what is involved may be found at the following URL:
http://www.vanwalree.com/optics/spherical.html

A desciption of the Veritar lens may be found at:
http://www.cameraeccentric.com/html/info/wollensakcatd/veritar.html
http://www.cameraeccentric.com/html/info/wollensakcatd/veritarb.html

[Bob Fowler]

Thanks Mike, I think I have a handle on it now.