Disassembly – Fujinon XF 18mm F2.0 lens

Fujinon XF 18mm F2.0 lens is one of first generation glass made for Fuji X-Pro1. It’s one of most compact Fujinon XF lens, and I was very interested to see how it’s mechanically designed, and if it’s easy to do some repairs or cleaning when needed. This article discovers disassembly steps and access to most mechanical areas.

I’d like to note first that accessing Fujinon XF 18mm F2 lens optics for cleaning is extremely difficult process that requires removing tons of factory glue. So if you need to clean a spec of dust or anything else from inner surface, prepare yourself for very challenging process. However if you need just lubricate moving parts or replace AF drive or electronic board – this is relatively easy process.

Disassembly steps

Step one is classical for XF lens – unscrew four silver and three black bolts, remove black plastic inner cylinder, release contacts module and finally remove mount ring.

You may find few tiny metal shims at mount bolt connection points. My lens has just one. Memorize shim position and put it back when assembling for proper optical alignment. Also, remove dark foam bar – it serves to hold electronics board in place.

Then unscrew two black bolts (marked in blue), and accurately release three ribbon cables. Make sure you don’t touch electronic board surfaces, keep it by holding edges – it’s important!

Now remove electronic board, but do not put it on the surface.

Electronic board has special section for aperture ring contacts, and it is covered with thin layer of lubricant. I never saw that in any electronic lens disassembled before, so be very attentive and don’t accidentally wipe that lubricant (or sealing gel, I don’t exactly know its purpose).

Then unscrew two black bolts and take out AF drive module.

At this point yo can unscrew three black bolts holding aperture ring module.

Remove aperture ring. You’ll see “focus by wire” focus ring sensors. To remove focus ring without damaging sensors, slightly press on it’s sides to make some space for sensors, then remove it.

Now you have good access to inner real focusing ring. I spent some time adding extra grease to focusing gear thread. You can manually rotate this ring to change core module focus position.

That is final disassembly point which can be easily done. Assemble lens back in reverse order.

However if you very much need to have access under the rear glass module the extreme challenge is starting at this point. I had to remove large 1.5mm wide dust particle, so I didn’t find other options but spend about 30 minutes accurately cutting out white factory glue piece by piece. It’s very messy process generating tons  of glue particles. After finishing that I also used very thin flat screwdriver to apply additional pressure between rear module plastic frame and lens core cylinder. Rotating rear lens frame about 15 degrees CCW allows to remove it.

I’ve spent another 10 minutes removing glue particles from surfaces, and used air blowing to remove most accidental particles traveled inside. As a result I cleared that huge dust particle under the rear glass, but it was hard process : )

Conclusions

Fujinon XF 18mm F2 lens has very interesting construction and electronics position. It’s relatively easy to disassemble lens mechanically and access electronics. However all the optics from rear side sits inside plastic frames firmly glued together. It’s not like XF 27mm where only few tiny glue drops hold rear module – XF 18mm has tons of solid and very hard glue. So accessing optics for cleaning is extremely difficult.

Front area disassembly

UPDATE [2020-06-21] Today I received very useful comment to this article from MARC GENEVRIER (thank you!) regarding front disassembly steps for XF 18mm lens. I performed few first steps to add more pictures to article.

I’m using double sided thick adhesive tape and empty frame from lens filter.

Unscrewing nameplate ring requires rapid torque movement CCW to break few dots of factory glue inside. Then it goes smooth until completely unscrewed from lens filter thread. Ring consists of two parts – thick plastic frame with side thread, and thin metal front plate with lens naming details.

There is also a foam ring to block dust from entering area around front lens glass. Now you can unscrew three black bolts holding filter thread ring.

After removing front ring you have better access to lens optical core. At this point I’m stopping disassembly, because this lens sample works great and is clean inside. However if I had to access aperture chamber my next step would be unscrewing remaining six bolts, and try to accurately break the glue to remain it on frame parts. It’s important to understand that optical frame position is precisely calibrated on Fuji factory and glue is applied to hold exact position firm. If you preserve the glue on all location, there is a higher chance you can put frame back in properly aligned place.

I see the similarity of frame design to XF 35mm F1.4. Looks like front metal plate around focus ring is also attached using adhesive tape. It can be removed, then you’ll be able also remove dust sealing ring and pull out focusing frame core.