This Fujinon GF80mmF1.7 R WR lens is designed for Fujifilm medium format GFX series digital cameras. It was launched on January 27, 2021 and marketed as “the world’s first*1 AF-capable F1.7 interchangeable lens”. GF80mmF1.7 R WR has a standard focal length of 80mm (a 35mm equivalent of 63mm). Its large-diameter autofocus (AF) prime lens features a maximum aperture of F1.7, which also makes it the fastest aperture lens among Fujifilm’s G Mount lenses. Lens designed to cover 44×33 mm GFX sensor and accept 77mm filters. Currently this lens is available in stores for price around $2300 USD new (USA) or about $1600 USD used. On Fujifilm website we can see get idea of internal design with moving central section for focusing.

It does not have OIS (optical stabilization) and can offer aperture from F1.7 up to F22. Aperture is defined with 9-blade diaphragm assembly. There are 12 optical elements in 9 groups, including 1 aspherical and 2 super-ED. Minimum focusing distance is 0.7 metre and focusing is done fully electronically with internal motor. WR in lens name means it’s equipped with Weather Resistance seals, which help with reliability. However neither lens nor GFX bodies have full water ingress protection, so be careful with Fuji GF 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.

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 block movements. Optics was looking nice and clean and no alien rattling could be heard.

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 expectations to make it working again. We can call it a sacrifice for science and gaining knowledge about modern GF lens internal design.

It’s time to teardown and see if we can find anything obviously broken inside. Modern lenses are complicated products with precision machining, clean and carefully aligned optical elements. They usually implement a lot of fragile thin flexible circuit boards and sensitive tiny electronic parts. Every component inside is custom made and is not available to buy as a spare part.

I am not a camera or lens repair expert, and I have no prior experience with repairing Fuji GF lenses.
If you need your camera or lens properly repaired and serviced, it’s essential to contact the manufacturer’s service center.
Do NOT attempt this at home if you’re expecting professional results and want to keep your equipment under warranty.

First we remove the G mount disk with electrical contact for the body. This is done by removing four large-ish chromed Philips screws. Carefully lift the disk to gain access to flexible circuit inteface cable to the electronic PCBA. Using fine tweezers unlock the latch up holding the cable and release the FPC gently pulling it out by tabs. Now we can see the electronic PCBA and some cabling inside:

Remove four screws and lift the outer barrel with “80” marking and “GF FUJINON” logo. This also releases the rear element lens group block, which can be just lifted up and placed aside. Once that is done we can detach four FPC cables from PCBA and remove it as well.

Flipping the lens we can get rid of the front barrel by removing 3 screws from the front and gaining access to front optical block. It’s mounted with plastic donut. Optical block is secured in place with grey clouded epoxy. We don’t need to remove it since there is no need to disassembly optical elements at this time.

Removing cover ring between aperture ring and focus rings reveals access to few screws that hold the focus ring barrel in place.

Be sure to disconnect thin 6-conductor flex cable from the rear section of the lens before pullung the focus ring off. Failure to do so would damage the flex.

Now with ring off we can better see the moving parts and bits. The central optical block is movable on the helix rails with circular bearings to provide focusing.

Let’s remove front lens block and investigate deeper.

Few more bolts gone and with front lens block removed we can see front of the focusing module optics, carefully surrounded by light absorbing black covers.

Metal ring can be also removed but it’s not helping much, as I didn’t want to remove the focusing optical block just yet.

Little brass stopper can be removed to release the aperture control ring. It is also only electronic ring and have no mechnical coupling to aperture unit inside of the focusing optical block.

Be careful at this step not to rip off the focusing drive flex PCB.

I’ve removed black mylar ring that blocks the parasitic reflections and internal light transmissions. This provided more access to the focus motor. Focus/aperture block was hard to move but seem to be going front and rear.

Digging a little bit more I managed to remove the motor drive for focus. Once motor was removed the lens block was freely moving smoothly and without resistance.
It has gear bearing which couples to the outer teeth on the focus/aperture optical block. Motor drive moves the block forward or backward depending on polarity of applied power. Motor has two wires suggesting DC drive.

I’ve used trusty Keithley 2400 SMU as a power source and applied 5.0 V with 300 mA current compliance. During the free moving current draw was about 40 mA. Positive polarity moved drive forward, negative moved backward. No issue was observed here anymore. There are some linear sensors attached to moving block as well, most likely with permanent magnet and hall-effect sensors.

Motor was embedded in the plastic housing with a gear. Gear had yellow grease for smooth turning.

There was a bit convoluted flexible PCB around with two wide conductors for motor drive and six thinner conductors, most likely for integrated sensor.

Motor was reassembled back into place and lens block was again locked in place. I left it in the middle position.

Look inside the lens shows another mother for aperture.

I did not disassemble the lens any further since it was interesting to see if it could show any different behaviour. Overall this Fujinon GF lens was relatively easy to take apart and investigate the construction. Compared to some older AF-S Nikkor zoom lenses I’ve taken apart before this GF lens is relatively simple.

To my surprise, after reassembling everything, the lens was recognized by the camera, and there were no more error messages. The aperture was accurately detected and could be controlled both by the camera and the lens ring. Focusing also functioned properly at both near and far distances. The next step will be to conduct some field tests.

Photographic tests

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 80mm f1.7 lens.

Aperture tests, close-up at minimum focusing distance.

All images were captured with 100S body mounted on a tripod with timer release. RAW files were processed in darktable and no additional sharpness or lens-corrections.

Image: Fujinon GF 80mm f/1.7 R WR with Fujifilm GFX 100S at f/1.7. Preview and 100% crop center. Click for 10942 × 7864 resolution (86 MP)

Reassembled lens is clearly soft at wide open f/1.7 aperture at this test. Gold lines are 0.1 mm wide with 0.1 mm spacing between them.

Image: Fujinon GF 80mm f/1.7 R WR with Fujifilm GFX 100S at f/2.8. Preview and 100% crop center. Click for 10942 × 7864 resolution (86 MP)

Softness still persist at f/2.8 but it’s significantly improved.

Image: Fujinon GF 80mm f/1.7 R WR with Fujifilm GFX 100S at f/4.0. Preview and 100% crop center. Click for 10942 × 7864 resolution (86 MP)

Stopping down some more shows good results for the center crop.

Image: Fujinon GF 80mm f/1.7 R WR with Fujifilm GFX 100S at f/5.6. Preview and 100% crop center. Click for 10942 × 7864 resolution (86 MP)

Reducing aperture even more does not show visible gains in sharpness.

Image: Fujinon GF 80mm f/1.7 R WR with Fujifilm GFX 100S at f/8.0. Preview and 100% crop center. Click for 10942 × 7864 resolution (86 MP)

Image: Fujinon GF 80mm f/1.7 R WR with Fujifilm GFX 100S at f/11. Preview and 100% crop center. Click for 10942 × 7864 resolution (86 MP)

Image: Fujinon GF 80mm f/1.7 R WR with Fujifilm GFX 100S at f/16. Preview and 100% crop center. Click for 10942 × 7864 resolution (86 MP)

f/16 shows up descrease in details and sharpness already due to diffraction. I wouldn’t use this lens past f/11 based on these quick check results.

Real-world photos

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 80mm f1.7 lens.

Some random photos were captured with evening light an hour before the sunset. All images were captured with handheld GFX 100S without artificial lights or flashes. All images were captured in RAW and processed in darktable.

Scenery photography

This 80 mm lens at large apertures below f/5.6 blurs the corners and out of focus objects quite smoothly.

Sunset position sun was right behind the tree trunk, testing the haze and backlit image contrast. Shadows were recovered +2 stops in RAW processing.

For next photograph below aperture was stopped down to f/8 with sun shining thru tree leaves. GF 80mm gives quite pleasant stars at this aperture setting.

Product photography

Friend of mine Arturo lend me a bottle of parfume as a test subject for the simple photo test. Camera was handheld and images were captured at ISO1600.

Dynamic movement

Captured some shots with moving cars on highway, at a distance about 10 meters away. Focus was set to fixed point and GFX 100S camera was handheld, tracking the movement of the car. Not the best shots but pretty interesting still.

Food photography

Summary and conclusion

I’m pretty happy with this project outcome and looking forward to play with this lens and GFX system. It feels like relearning photography from the basics again after shooting with Nikon F bodies and lenses for 16 years. I got few more broken GF lenses for future teardown projects as well, so stay tuned and keep checking for updates.

Also real-time discussion about this article and related stuff is very welcome at xDevs.com IRC-chat server: xdevs.com (standard port 6010, channel: #xDevs.com).