This GF63mmF2.8 R WR lens is designed for Fujifilm medium format GFX series digital cameras.

Image 1: GF63mm f2.8 Lens design

WR in lens name means it’s equipped with Weather Resistance seals, which help with reliability in the field. However neither lens nor GFX bodies have full IP67 water ingress protection, so be careful with Fuji GFX system in the inclement weather outings.

I’ve heard of Fujifilm before when I was shooting on Nikon D80 and DSLR were all the rage. Fujifilm back in 2006 had special version of D200 camera body with their own 6.17 MP CCD sensor and electronics, called Finepix S5 Pro. S5 Pro was famous for it’s unique color rendition, compared to more common D200. There was even more special FinePix IS Pro version full spectrum with light sensitivity from 380 nm to 1000nm, capable capturing NIR and UV.

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Issue with the lens

For testing I’ve used GFX 100S and 50S II bodies. Once lens is attached test camera reports the lens fault with message “TURN OFF THE CAMERA AND TURN ON AGAIN” and would not let user do anything, locking out all the controls. Both GFX 50S II and GFX 100S were reporting same problem with this lens.

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Image 2: Unhappy camera reporting lens error

Turning focus or aperture rings did not do anything. Focus ring was turning smoothly but like all other GF lenses it’s not mechanically coupled to inner focusing blocks movements. Optics internally looking nice and clean.

Teardown

With such condition, lens was unusable since it could not be focused or controlled from the camera. I was also interested to see how it is built internally and if it’s something simple internally like a damaged coupling or broken part. Lens was written off already and there are no much expectations to make it working again. We can call it a sacrifice for science and gaining knowledge about modern GF lens internal design.

Most likely this lens was dropped or had frontal impact, getting the moving frontal block jammed in. When attached to camera it has just little blip and nothing else.

Externally everything looks pretty good without cracks or damages.

Some finger prints here and there but nothing too bad visually.

Removing mount plate reveals access to rear lens block, metal chassis and glimpse on PCBA.

Aperture ring is same as with other GF lenses and easily removed by pulling gently up. Don’t loose the ball bearing that provides that nice “click” on each stop position.

Detach some flex PCB and remove the rear lens block.

Next step is to detach front metal ring held by double-tape adhesive in few spots and unscrew plastic ring around the front element. Unlike the more expensive 80mm f1.7 and 120mm f4 Macro front ring is plastic in this cheaper lens.

Now we can remove the front cylinder body and gain access to remove the focusing ring next step. Here it is also apparent a damage on the plastic body that surrounds the front lens block. This further suggests the impact from the front, but somebody was already in this lens before me, as no debris or broken off bits could be found.

After removing focusing ring we can finally gain access to the lens core. Front lens block supposed to move forward and backward for focusing. We can see a little DC motor with gear teeth on the helix body.

There is a bit of white color grease around to help with smooth turning, but actual helix is stuck pretty bad. I had to apply quite a bit of force by hand to get it moving. No way that little motor could apply such torque.

Disconnecting the motor is easy enough and then helix with lens block are moving actually much better. Connecting lens to the test GFX body in this state let it be recognized without error. But as soon as the motor gets stuck again, we back to the original error message.

Taking motor apart revealed just two little gears and a worm gear with optical encoder on the motor shaft. Inspection under microscope didn’t reveal any cracks or shaved teeth. Motor was able to turn on it’s own when powered by Keithley 2400, using just about 80mA.

Taking lens unit out to inspect helix and teeth on it also revealed no obvious problems.

PTFE spacers are a little bit worn out but even without lens unit attached to the helix motor gets stuck and unable to turn it smoothly.

At this point I’m bit lost what to try next. Maybe there is a tiny crack in one of the gears that gets larger and causes a jam once the load is applied?
I could try 3D print the gears on a resin printer and see if that helps, but something tells me that wouldn’t be very successful as gears are pretty small.

Update

Thanks to second incomplete broken GF63mm lens I’ve replaced the front/aperture lens unit with helix mechanism and it was moving silky smooth. After reassembly one full lens out of the parts from two bad ones we got a good working unit.

Sample images with fixed GF 63/2.8 lens

These tests were conducted on a lens that had been patched up, as discussed in this article. Therefore, the results are likely not representative of the actual performance of a good and properly functioning Fujinon GF 63 mm f2.8 lens.

All images were captured with GFX 100S, handheld. Photographs are available in full resolution after click.

Panoramic stitches

All images are available in full resolution after click.

Summary and conclusion

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