Cooke Portrait PS945 Lens 229mm, f/4.5 for 4x5 Large Format Photography

4 July, 2008

Cooke Optics Ltd.
Cooke Close
Thurmaston
Leicester, LE4 8PT
United Kingdom
T +44 (0) 116 264 0700
F +44 (0) 116 264 0707
lenses@cookeoptics.com

We have temporarily suspended production of our large format lenses. Watch here for production updates.

"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

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 take 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.

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.

Testimonials and Sample Photos

Attention Owners of the Cooke PS945 Lens: Photographer Don Tsusaki, is forming a user group exclusively for owners of the Cooke PS945 lens for sharing information, tips and techniques. Owners may contact him at info@photoverge.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.

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.

Links to more sample photos taken with the Cooke Portrait PS945 lens:

Cooke Portrait PS945 Lens Technical Information

Format	4x5 inch

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.