Repair - broken focus - Fujinon XF 35mm F1.4 R lens

This broken Fuji XF 35mm F1.4 lens sample got purchased from eBay. It was listed as “for parts” and mentioned that camera is often asking to restart with this lens. I decided to explore lens and see if it can be repaired, or I just use it for manual conversion.



Lens worked and focusing on my X-T30 camera but I noticed that lens core is heavily tilting when focusing – about 5-10 degrees. I focused lens to minimal distance then disconnected from turned on camera to keep focus in that mode. I was able to freely tilt lens core in one direction which indicated that some guiding mechanics is broken inside. Shaking lens unveiled some noise like small part or bolt is moving inside.


Disassembly and repair

You can check Fuji XF 35mm F1.4 disassembly steps for more details of typical disassembly process for this lens. This time broken lens required few extra steps:


Unscrew two black bolts blocking inner focus ring rotation.

Remove black metal ring plate from the focus ring front, then accurately remove felt strip from inner circle.

Rotate focus ring to make lens core move out, then pull lens core out.

Now the problem is clearly visible. Plastic part holding metal pin got broken most likely from frontal hit to the lens. Pin felt out and lens core didn’t keep its position, which resulted to wrong focusing.




I’ve cleaned surfaces from the grease and used strong glue gel to connect plastic part (fortunately it was still inside). After that I’ve added more glue and secured metal pin inside.





After a minute I’ve removed glue extras and accurately polished plastic bar sides to make them flat again, it required fine grinding of plastic as well because breakage deformed part of plastic side. Finally I’ve added some grease on top.



NOTE: Insert lens core back and rotate focus ring few times to make sure core is moving easily. Otherwise extract the core and polish the pin area plastic and add grease again.


After assembly this Fuji XF 35mm F1.4 works perfect. Lens core keeps proper position when focusing. So looks like I’ll just keep the lens in regular electronic mode and will look for another broken options for conversion.


Conclusions

Fuji XF 35mm F1.4 lens can be significantly damaged by frontal hit impact to the side of extended lens core, e.g. when camera falls on the ground with lens facing down, or hitting some object while carrying. That plastic area holding guiding metal pin is only 1.5mm thick. Fortunately it is possible to fix this mechanical issue and bring Fujinon XF 35mm F1.4 lens back to life.

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