Cooke Lens Service

MOHR Lens Service repairs, services and recalibrates Cooke cinema lenses from a dedicated optical and CNC workshop in Solna, Stockholm, serving rental houses, owner-operators and cinematographers across Europe. As a Cooke-certified technician, I am trained across the range up to and including the S8/i primes and the Cooke anamorphics — the most mechanically demanding lenses in the lineup — and the newer compact series sit well within that scope. I also offer uncommon depth on the older glass that rental fleets send out for service: the Speed Panchros, early S4 primes and the Varotal zooms. All work is carried out by one person, start to finish, with nothing subcontracted out.

What I service on Cooke lenses

• Full CLA (clean, lubricate, adjust) on primes and zooms
• Parfocal calibration and back-focus / flange depth correction
• Cam and follower diagnosis and repair on Varotal zooms
• Focus and iris mechanism overhaul — smoothing, re-greasing, backlash removal
• Optical cleaning, separation and haze assessment
• Custom part fabrication when factory spares are unavailable (CNC and lathe)

For how every lens is tested and verified — including projection testing, collimation, mount conversions and the work I don’t take on — see the Cine Service page.

Cooke zooms — from Super 16 to the large-format Varotals

Cooke’s zoom range is wide, and across my career I have serviced examples of every Cooke zoom series I am aware of — from the Super 16 zooms, including several highly sought-after models, through the classic Super 35 Varotals (18–100, 20–60, 20–100 and 25–250) to the larger S35 and full-frame zooms such as the 40–400. I am also familiar with Technovision-modified Cooke optics, such as the faster 18–90 built from a modified 20–100 Varotal.

The Varotals are where most zoom service requests land, and where the hardest problems live. A zoom that has drifted out of parfocal — sharp at the wide end, soft when zoomed in — is usually not an optical fault but a mechanical one: cam indexing, worn cam follower rollers, or flange and shimming that has shifted over the years.

Case: Cooke 18–100 Varotal — saved with custom-made parts and all-new roller bearings

This Cooke Varotal 18–100 arrived with play in the mount, image shift while zooming, and an artificially limited zoom range. Someone had clearly made a brave attempt at repairing it before — and this is genuinely one of the trickiest zooms to get right — but a few of those fixes were masking the underlying faults rather than solving them.

[BILD 1 — t.ex. den isärtagna zoomen vid ankomst / cam-mekanismen]

I machined 17 complete new roller bearing assemblies with new miniature precision bearings, replacing all the originals. The rollers are turned from a high-performance engineering polymer normally found in aerospace applications — extremely dimensionally stable and wear-resistant, ideal for zoom mechanics where every micron of roller geometry translates directly into image steadiness. One of the old rollers turned out to be cracked — the cause of the image shift.

[BILD 2 — t.ex. de svarvade följarrullarna / precisionslagren]

I also CNC-machined a new PTFE cam follower, made new custom screws and other small parts, and serviced the mount and sub-mount until perfectly solid and straight. The limited zoom range traced back to an incorrectly indexed zoom cam — I corrected it and removed the artificial stop added in an earlier repair. Finally, a full parfocal recalibration on the collimator, with elements and mechanics cleaned throughout. Ready for many more years of service.

[BILD 3 — t.ex. färdig lins / projektor- eller kollimatortest]

Cooke primes — from Speed Panchro to S8/i

Prime service is mostly CLA, focus and iris feel, optical cleaning and mount truing. The Speed Panchros and early S4s benefit from someone who has had many of them apart — grease choice and reassembly torque make the difference between a lens that feels factory-fresh and one that merely feels “serviced.”

Why send a Cooke to MOHR

• Cooke-certified, working solo — the person who quotes the job does the job
• Full CNC and lathe capability in-house for parts that no longer exist as spares
• Projection testing, optical bench and vertical collimator for diagnosis and verification
• Based in Stockholm, serving rental houses and owner-operators across Europe

To discuss a Cooke service or get an estimate, get in touch via the Contact page.