
Cooke Portrait PS945 Lens
The PS945 lens is a versatile visioning tool: Wide open, at f/4.5, you will see a beautiful glow in the highlights with no loss of sharpness or resolution. (See the sample photos taken with the Better Light digital scanback system.) Stop down the lens to f/11 and higher and note the stunning look of the out of focus areas of your image. The characteristics of this lens are unlike any other.
The original design of this lens is from the vintage Pinkham & Smith Visual Quality Series IV Soft Focus Lens used by early 20th century master impressionist photographers. These talented photographers made soft focus photography an art form using, most notably, Pinkham & Smith lenses, yet today, this original lens design offers much more. Use the Cooke PS945 to capture portraits, fashion, landscapes, weddings and for artistic experimentation. It lends an emotion to product shots that you just can't achieve afterward in Photoshop.
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.
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.
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.
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 Technical Information
Format
4x5"
Effective Focal Length
229mm/9 inches
Aperture Range
f/4.5 to f/90
Optical Construction
4 elements in 2 air-spaced doublets
Iris Scale
One engraved scale marked at full stops
Angular Rotation of Iris Scale
68.5 degrees
Format Angle of View
45 degrees
Front Lens Clear Diameter
62mm
Image Circle at Infinity
190mm
Shutter Speeds
1 to 1/125 seconds, T, B
Filter Size
77mm
Front Internal Mounting Thread
M77 x 0.75 pitch x 5mm long
Front Mounting Diameter
80mm
Shutter Diameter
102mm
Clearance Diameter for Shutter Levers
134mm
Shutter External Mounting Thread
M62 x 0.75 pitch
Flange Focal Distance
216.8mm nominal at infinity
Location Bore in Lens Board
Standard for Copal #3 Shutter, 65mm using supplied clamp ring
Overall Length
90mm
Weight
0.73 kg/1.6 lbs.
External Finish
Semi gloss black anodise with textured gold bevel ring
The Lens is Supplied with the Following
- 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.
- 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.
"The lens can be used with great success as a 'soft focus portrait lens' but it really is much more. For the still life photographer it represents a new tool that can add a different tactile feel to black and white as well as color images. And for the f64 purists: we are NOT talking pictorialism, no mush or fuzzy imagery!"
Per Volquartz
Per Volquartz

Portrait of a Farmer
Taken with a PS945 lens
Photo by Gregor-Alexander von Ehrenfels.
Copyright Cooke Optics Limited.
Watermark Security by Digimarc.
"Wow. This gorgeous piece of hand-crafted brilliance arrived on my doorstep today. Into the garden I ran, mounted the lens on my 5x4, tucked my eager head under the cloth...and the sight on the ground glass was utterly spectacular. Almost 3D at large aperture, moving in a most subtle way to sharp as my modern landscape lenses as I stopped down. Both thank you and congratulations to your whole team. This is a wonder. For those of us who shoot portraits outdoors in light, the coating and lack of flare is a dream come true. Indeed, I can see just leaving this on when the subject leaves and I decide to go ahead and shoot the land. A true marriage of the best the Pinkham & Smith's had to offer with the practicality of modern engineering. Again, thank you. This is a lovely lens."
John Wood
John Wood
Attention Owners of the Cooke PS945 Lens: Photographer Don Tsusaki formed a user group exclusively for owners of the Cooke PS945 lens for sharing information, tips and techniques. Owners may contact him at PS945@zitherist.com for information. Read his critique of the PS945. (PDF 2.29 mg)
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.
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.