Disassembly – 7Artisans 35mm F1.2 lens Fuji X mount

 Today my goal was to fix small problem with disconnecting 7artisans 35mm F1.2 lens from the Fujifilm camera mount. During recent 7artisans 35mm F1.2 lens review I’ve realized that this lens can stuck when the lens lock pin of the camera catches one of lens mount bolt location. So I’ve disassembled the rear area to see what can be done.

Fix issue with dismounting lens form Fuji X camera

My 7artisans 35mm F1.2 sample had this problem – camera lock pin catches one of lens mount bolt frame preventing unmount rotation to complete (unless you keep lens lock button pressed all time).

I’ve temporary solved that during recent lens disassembly by under tightening the bolt. Better way to fix is to add extra shim on that bolt (in addition to 3 aluminum shims installed on factory) so it can be securely tightened. I’ve cut the shim from 0.2mm copper plate.

That extra 0.2mm make a difference, allowing bolt to be securely tightened, and stay lifted enough to the exact level of lens mount surface.

Lens mounts and unmounts smooth with Fujifilm X-E2s after the fix. Nice : )

BTW, I’ve also added drop of red paint on the lens frame, now it’s more convenient to see which aperture value is set.

Rear area disassembly

You will need T6 Torx screwdriver to start the disassembly.

First, gently unscrew all three T6 bolts, they are nicely secured with blue adhesive so little effort is required. After that you can take off the mount ring, aperture ring, and may optionally unscrew one of the inner ring (better skip that for now).

Important NOTE: my sample has three tiny shims on one bolt located near the lens lock socket. I think that 7artisans factory are familiar with “mounting lens” problem, and it looks like one of possible easy solution. They just added 3 shims to lift up the T6 bolt head. Probably my sample has this bolt a bit overtightened, so it’s not lifted up enough. I’ll check it when assembling the lens back, and tightening it properly (or adding extra 1 shim) should solve the problem.

Why to stop now, I’d like to go forward a bit. 7artisans lens has click-less aperture ring. I want to discover how it is implemented to see if I can modify it later to click-stop version.

Gently unscrew the First aperture bolt shown above. Why first? This bolt is just a part of more complex system. After unscrewing it you can pull out inner aperture “transmission” ring that transfers rotation to the Second aperture controlling bolt.

I like that solution, it definitely gives few options to add click-stop mechanism at the place where this “transmission” ring is located. Hmm, I’ll probably do that in the nearest future : )

I’ve marked the rear lens group frame position and tried to pull it out, but it didn’t go. Well, not required now so I’ll stop disassembly at this point, as there are no dust inside to clean. What I like to see here are another Torx bolts are used to secure helicoid guiders – 7artisans engineers really like Torx bolts : )

One more view from the side. The long silver scratch was there initially, looks like factory scratch. The helicoid has plenty of grease everywhere which is great to see. You can easily lubricate it in the future with simple access to many areas at this point.

Few more observations. The silver mount rings is very light – 1/2 Oz (16g), which means that more light alloy is used ant probably it’s not solid brass (it also has yellowish color). I’ve made mount bolts frame edges smooth and then assembled the lens back.

During tightening T6 bolts I’ve tightened the one with three shims to a bit higher position, so its cap is on the same level as mount surface. After that it’s super easy to disconnect the lens from camera.

Front area disassembly

June 21 2018

Today I’ve disassembled front area of 7artisans 35mm F1.2 lens. It may be useful if you need to clean front glass elements, repair filter thread or lubricate the helicoid focusing ring.

Front metal ring with letters can be unscrewed CCW using rubber cylinder for lens disassembly. It’s secured in the thread with three small point of glue, and later I discovered why. Keep lens fasing up during this process.

Under the ring you will see three small bolts. They are securing front filter thread ring.

NOTE: I’ve turned lens to the side for few shots below, but please don’t do it.

Because the front glass element will unexpectedly fall out. That front ring with letters was actually holding glass on place, that’s why 7artisans add glue to the ring thread.

It’s nice to see that even this first glass element with very thin borders has darkened contours.

Next step is to unscrew three bolts and pull out the filter thread ring.

At this point you can loosen three Torx bolts on the focus ring and also pull it out. Focus ring has stopping pin right under the “infinity” mark. I like that outer silver helicoid has machined thread for focus ring bolts, so it sits very secure there.

NOTE: Looks like the bolt size is T2, I’m using quite old T3 bit (to the right on picture), it fits because shape is angled on the end making it closer to T2 size. My another T3 screwdriver does not fit inside (left one on picture) because edges are more straight.

I’ve collapsed helicoid to check how compact is the 7artisans 35mm F1.2 lens inside.

If you look closer on the lens body ring with DOF marking, there is separate thread for focus ring stopper pin. Technically that pin can be cut to little extend the minimum focusing distance of the lens. TO my taste focusing on 0.35m distance is close enough, so I’ll not do that.

At this point it’s easy to remove all the front glass, but I didn’t have real need to do that – amount of micro dust inside of my lens sample is too low. So I’ve just assembled the lens back and re-calibrated infinity focus.