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Cooke S4i

Award winning Cooke S4 Prime Lenses were designed and developed in close technical collaboration with industry professionals. They are colour-matched and compatible with Cooke’s, 18-100mm T3.0 and 25-250mm T3.7, 15-40mm, T2.0 CXX zoom lenses and the SK4 16mm lenses.

Cooke S4 optics offer superb optical and mechanical performance, control of flare, distortion, veiling glare and spherical aberrations at full aperture. The cam-type focus mechanism allows for smooth focus adjustments. Modular construction increases ease of maintenance and serviceability.

All of our S4 Prime lenses (and CXX zoom lens) are now supplied equipped with /i Technology, as of February 2005. S4/i lenses are designed for all PL mounted professional motion picture film and electronic cameras. The i Technology provides cinematographers and camera operators with vital information on lens setting, focusing distance, aperture and depth-of-field, hyperfocal distance, serial number, owner data, lens type and focal length in both metric and footage measurements. For zoom lenses, the zoom position is displayed.

For companies interested in producing compatible products with /i Technology, the /i protocol is available as a free download: See “S4/I Communications v2.28 protocols” in PDF format under Technical Resources,

65 Soft Effects Attachment

The 65 Soft Effects is made for the S4/i 65mm and 75mm lenses (via Cooke 75mm adapter ring). The design for the attachment is based on Cooke’s PS945 soft focus lens for 4×5 large format photography. See the effect in sample photos taken with the PS945 lens. The effect is high resolution with a stunning glow to the highlights — subtle, but most pronounced wide open at T2, becoming less pronounced as you stop down. (Effect from T2 to T4 with the 65mm lens; T2 to T5.6 with the 75mm lens.)Hide Details.

Using the S4 Soft Effects Attachment With the Cooke S4/i 65mm and 75mm Prime Cine Lenses

The Cooke S4 Variable Soft Effects Attachment is designed for use on the 65mm and 75mm S4 cine prime lenses. Depending on the aperture used, a variable degree of softness can be applied to the image. The soft effects attachment fits directly on the 65mm S4 lens, and for this reason it is engraved as being for that lens. If you want to use it on the 75mm S4 lens you need to use the Cooke adapter ring which is engraved for use with that lens.

Adjustment of the Soft Focus Effect

The soft effects attachment delivers a range of soft focus effects with the 65mm and 75mm S4 lenses as the aperture is varied. For the 65mm S4 prime lens the soft focus effect is greatest at T2, reducing to no special effect at T5.6. At apertures below that, the lens operates as a normal, sharp lens. The 75mm S4 lens provides the same effects, but when this lens is stopped down to T4 it is already fairly sharp.

In general, if you want a particular degree of softness you may need to use neutral density filters.

Comparison with Soft Focus Filters

The Cooke soft effects attachment works in a completely different way to nets or soft focus filters. Rather than bluntly scattering the light, it uses a higher order aberration effect to reduce sharpness at lower spatial frequencies in the image. It follows that the change in its effect with aperture is much more pronounced than with a soft focus filter or a net. Roughly speaking, a net or a softening filter has the same effect at all apertures; that is not quite the case, but certainly there is much less variation of softness with aperture when using nets and filters than with the Cooke Soft Effects Attachment.

The Origins of the Soft Effects Attachment

The origins of the Cooke Soft Effects Attachment are in Large Format Still Photography, with our Cooke PS945 Lens for large format photography: Cooke Optics Ltd. manufactures a highly acclaimed large-format stills lens for the 4×5″ and 7×5″ formats using this soft focus technology, which provides the same variable degree of softness.

At the request of the large format photographic community, this lens is based on the revered Pinkham & Smith portrait lenses of the early 20th century. Use of the Cooke PS945 lens by many professional large format photographers has, ironically, now revealed at least as many non-portrait applications for this lens as portrait applications. The ability of the lens to provide what is described as a “unique, and special luminosity” to the image with a range of lighting arrangements is especially valued. Hide details

Lens Awards

Cinec Award for Technical Excellence, Germany
Academy of Motion Picture Arts and Sciences Scientific and Engineering Award for Optical and Mechanical Design
Primetime Emmy Award for Outstanding Achievement in Engineering Development
Two Queen’s Awards for Enterprise – International Trade and Innovation, England
Winner, Exporter of the Year, 2001 International Business Award, Export Times and Trade Partners UK
Winner, Product Innovation, 2001 International Business Award, Export Times and Trade Partners UK
NAB2007 Premiere Product Award – S4/i System

Click into “Accessories” tab and link to lens specifications for each S4 Prime lens.

Performance Superb control of flare, distortion, veiling glare and spherical aberrations at full aperture.
Focus Mechanism The S4 design foregoes the usual helical thread method of focus adjustment in favour of Cooke’s Academy Award®-winning cam mechanism. The smooth cam movement liberates the lens from a simple thread rotation giving the operator an appropriate rate of focus at all distances. The cam design also allows for better spaced and more detailed and visible index marks.
No Breathing No image shift when racking focus from close focus to infinity.
Color Balance All focal lengths are color balanced, achieving excellent contrast and resolution over the full Super 35 format.
True T2.0 Aperture Cooke Series 4 lenses are optimized at maximum aperture, measured at a true T2.0. The Cooke S4 300mm lens is measured at a true T2.8.
Operation Focus and iris drive gears have the same diameter and position across all focal lengths reducing adjustment time when changing lenses: 140 teeth 0.8 Metric Module x 6.0mm Wide (98mm from image plane)
Iris Scales  Two opposing linear T-Scales, whole and third stops marked
Iris Angular Rotation Total Rotation 91 degrees.
Iris Drive Gear 134 teeth 0.8 metric module x 4.0 wide x 79.5 from image plane
Mount and scales Each of the Series 4 Primes are supplied with PL mount and are available with either footage or metric focus scales.
Finish Hard-wearing, scratch-resistant, PTFE anodised finish for working in the harshest environments.
Internal Front Fitting Filter Internal Thread for Filter Adapter M105 x 0.75 pitch
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