Cooke Portrait PS945 Lens
Quality of Diffusion
The quality of diffusion is midway between the softness of the first Pinkham & Smith Semi-Achromat lenses made in the late 1890s and a conventional sharp lens. It performs just like the rare and revered, original Pinkham & Smith Visual Quality Series IV lenses that were produced in Boston, Massachusetts in the early part of the 20th century.
Degree of Diffusion
The selection of aperture controls the degree of diffusion. Your choice of subject, lighting conditions and final processing will influence the final print results, but in general you will achieve the following effect: At f/11, the lens performs like a conventional sharp lens but without the unattractive, out-of-focus background that would be imaged by most conventional lenses. At f/8, the lens will produce a sharp image but absent an unpleasant hard edge. At f/5.6, the image appears more velvety but in focus with a subtle roundness of the edges. At f/4.5, the lighter areas appear to generate their own luminous glow without losing focus, or losing the contrast against the darker areas.
Soft Focus Lenses versus Diffusion Filters
Using a soft focus lens is not the same as using a diffusion filter on a conventional lens, nor is it the same as stopping down a conventional lens. A diffusion filter causes a random scattering of the rays at all points across the aperture. The image obtained with a soft-focus lens retains all of the subject detail over a wider depth of field than with a conventional lens set to the same aperture, but the emphasis on the fine detail or the bolder elements of the image can be distributed as the photographer wishes.
The original Pinkham & Smith lenses achieve their distinctive soft focus in a manner different from other lenses. Using the traditional glass available at the time, craftsmen hand-corrected multiple surfaces of the lenses to achieve their unique soft focus look. The introduction of aspherical surfaces gave Pinkham & Smith lenses a higher-order spherical aberration that results (when the lens was used fully open) in an image with both very high resolution and a self-luminescent quality. Cooke has reproduced the unique performance of these hand aspherized lenses using modern design techniques that duplicate this unique soft yet high-resolution performance exactly.
- Cooke Portrait PS945 lens in Copal #3 shutter
- A CD containing a short primer authored by Jay Allen entitled, "How to Use a Soft Focus Lens, Featuring the Cooke Portrait PS945 Lens," technical specifications, historical data about Pinkham & Smith lenses and the Cooke brand of lenses, and sample photos taken by contemporary photographers using the Cooke Portrait PS945 lens.
Portrait of a Farmer
Taken with a PS945 lens
Photo by Gregor-Alexander von Ehrenfels.
Copyright Cooke Optics Limited.
Watermark Security by Digimarc.
Better Light, Inc. digital scan backs and the PS945 lens: A Heavenly Combination. See stunning test images.
Mark Osterman, process historian at the George Eastman House, Rochester, New York, tested the Cooke Portrait PS945 lens. Read his observations.
Clive Russ, photographer, shares his photos that highlight the velvety gradation between in-focus and out-of-focus areas.
Bill Katzenstein, IconicPhoto, Washington DC, shared his observations and a sample photo.
Jay Allen, author and photographer, tells about the versatility of the Graflex Series D camera with the PS945 lens.