Custom Lens – Fujinon 27mm F2.8 Industar mark II – M42/FX mount

One more Fujinon XF 27mm F2.8 lens sample required custom conversion. It also had dead electronics, so I purchased another one Industar 50mm F3.5 lens in M42 mount for this project. Lens conversion principles are similar to explained in this article, though Mark II version is even more minimalistic.

Updated schematics of this conversion:

First noticeable difference to previous mod – absence of Industar outer frame ring with DOF scale. Lens core is durable enough without that ring, and lens body becomes really tiny.

Second difference is – removed aperture/focus ring markings. It makes lens look very minimalistic and simple.

Of course I had to cut off about 3mm of focus ring again.

I’ve also redesigned the way front plastic plate is attached. Now it has two rectangular slots at borders that allow to tighten that plate inside front filter thread.

It’s not very easy to detach lens from M42/FX adapter due to much smaller ring to grip, but I don’t plan to do it often.

Adapter flange is 5.5mm, so about half of lens core sits inside it. The view below for lens focused to infinity. This time I’m calibrating infinity focus precision by moving front optic module inside Industar aperture ring frame.

This Fujinon 27mm F2.8 Industar mark II has shorter focusing movement

Rear Fujinon 27mm optical module is secured in same way as in previous version – using rubber o-ring.

The M42/FX adapter ring now has clearly visible two red strips for quicker mounting of this super compact lens on Fuji camera.

Of course this lens can be mounted using standard M42 macro tubes for extreme close up shots. Another positive side of such adaptation – lens can be mounted to another APS-C system camera like Canon or Sony with corresponding slim adapter.


    • Optical IQ is very similar as any other Fujinon XF 27mm F2.8. One difference is that camera doesn’t know the lens and does not apply automatic digital corrections which are typically applied to all Fujinon 27mm lens shots. Another difference is the close up field curvature – just because standard XF 27mm lens has front module moving when focusing, and in this adapted version – whole optics is moving, which brings more distortions to image corners at close focusing distances.

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