Imagon Lens, what is it?greenspun.com : LUSENET : Large format photography : One Thread
I am considering buying a Deardorff Special for my first and only 4x5. A Imagon lens could be part of the package. What is an Imagon and what are it benefits and liabilities?
Thank You, Ken
-- Ken mcCormack (email@example.com), November 14, 1998
It is a specialized portrait lens made by Rodenstock that allows you to vary by means of interchangable disks b=combined with f/stop the degree of diffusion from none to quite intense. to quote from the 1998 B&H "bible": "The imagon lenses do not produce the blurred images known from incorrect focusing or poor quality lenses. It rather overlays a clearly defined image core with delicate diffusion, controlled by adjustable push-on perforated diaphragms. By spreading highlight outlines into the shadows, the Imagon softens the hard definition, yielding portrait or landscape effects that range from a slightly flattering rendering to dreamy, romantic moods. Optical design: 2 elements in one group." New prices for the various focal lengths run from US$1660 to $1730.00
-- Ellis (firstname.lastname@example.org), November 14, 1998.
Except for the comment about apertures the answer from Eliis is correct. However the aperture on the Imagon is always wide open. Apertures are controlled by the disk used (3 disks for Imagons up to 250mm, 2 disks for the 300mm) and weather the disk is used open or closed.
Each disk consists of a center hole surrounded by smaller periphical holes. The surrounding holes can be used open or closed. The more open the surrounding holes the "softer the image" Each disk consists of different size center holes. The disk with the smalles center hole delivers the sharpest image. The disk with the largest hole the softest image. Using no disk is the softest effect.
To work properly the Imagon requires strong spectral highlights, not soft lighting. Usually a contrast ratio of 5:
-- Bob Salomon (email@example.com), November 16, 1998.