Cinema lenses are precision instruments. A zoom that tracks poorly, a focus that binds, an iris that sticks — these are not inconveniences. On a shoot, they are problems that cost money and time. MOHR Lens Service exists to fix them properly.

What I do

Most service work falls into familiar categories: CLA (clean, lubricate and adjust), parfocal calibration, back-focus adjustment, mount conversions, gear fabrication, and the replacement of worn or damaged parts. Surface refinishing — re-anodising or repainting individual parts or complete housings — is available for lenses where appearance matters as much as function. But cinema lenses rarely present familiar problems.

What sets MOHR apart is the ability to go further. The workshop is equipped with a CNC mill, lathe, and precision measuring equipment — which means that when a part is worn beyond adjustment, or simply no longer available, it can be machined from scratch. Custom cam followers, eccentric pins, torsion springs, focus gears: if it can be made, it can be made here. This matters most on the lenses that matter most — older glass, rare zooms, lenses that a standard service facility would turn away.

How lenses are measured and verified

Every lens is checked on a lens projector, not only a collimator. The workshop uses a Chrosziel projector, modernised to cover large-format sensors up to and including ARRI Alexa LF and Mini LF (and equivalents such as Sony Venice and RED), so modern full-frame and large-format lenses can be tested as readily as Super 35 and Super 16 glass. Projecting the image at high magnification reveals what a collimator alone cannot: field curvature, image shift through focus, decentering, and whether the focus scale actually matches where the lens resolves.

The projector accepts PL, LPL, Sony E, Arri Standard and B4 mounts directly, and most other lens types through Sony E adapters — so the great majority of cine and stills lenses can be mounted and verified. Alongside the projector, a vertical collimator is used for collimation and re-cementing work, and an optical bench for finer optical assessment. This is how a parfocal fault, a tilted element or a mismatched focus scale is diagnosed precisely, and how every result is verified before a lens leaves the workshop.

Mount conversions and mechanical modifications

A common reason to convert a lens is that its original mount is no longer made, or no longer fits the camera it needs to run on — typical of older glass built for mounts that have long since fallen out of use. Most conversions are to PL, sometimes to EF, and increasingly to LPL as large-format cameras become more common. I design and fabricate these mount solutions in-house, converting older mounts such as Mitchell BNCR, Arri Standard and M42 to a modern mount with the back-focus and flange depth set correctly, so the lens performs properly on the intended camera.

I also install and calibrate off-the-shelf mount adapters so that back-focus and parfocal tracking are genuinely correct rather than approximate — fitting one properly is precision work, not a simple swap.

What I don’t do

Honest scope keeps the right work coming in. I do not take on full rehousing — stripping optics from their original barrel into a completely new cine housing is time-intensive, and others do it better; I am happy to point you toward specialists for that. Mount conversions, custom mount solutions and mechanical modifications, however, are very much part of the work — see above.

How it works

When a lens arrives, it is tested fully: optics, mechanics, feel, and visual condition. From this, a written report is compiled with findings and recommendations, along with a cost estimate. Nothing is done without sign-off. Work is carried out by Martin Rodensjö, certified by ZEISS and Cooke. Every adjustment is documented. A vintage lens that leaves this workshop may still look its age — but it will perform like new.

Who I work with

Rental houses, owner-operators, and cinematographers across Sweden and Europe. If you are unsure whether your lens is a candidate for service, get in touch — an initial conversation costs nothing.

Rates →