Disassembly and repair - TTArtisan 35mm F0.95 lens in Fuji X mount

This article shows how to partially disassemble TTArtisan 35mm F0.95 lens and enable infinity focus calibration

TTArtisan 35mm F0.95 is a great tiny lens with impressively fast F0.95 aperture for it's compact size. There is very well known ZhongYi Mitakon 35mm F0.95 lens and its lightweight successors made by 7Artisans and Risespray with almost identical optical formula and performance.

Looks like TTArtisan decided to use simplified optical design with smaller number of glass elements. It leads to more simple optical mechanics too, in this lens while optical core moves as solid block when focusing (and Mitakon lens has static rear optical element embedded in mount frame).

I purchased TTArtisan 35mm F0.95 lens in Fuji X mount from one of eBay distributors and luckily received very good copy with well centered optics (tested on Siemens star chart). The central sharpness is very comparable to Mitakon and OOF blurring look quite natural and interesting. It is definitely lens with its own character and needs some practice to shoot with.

My lens copy is slightly overpassing infinity, which is OK, but is a bit annoying. The lens focusing ring has three bolts for calibrating its radial position and fine tuning infinity focus stop. However unscrewing them does not release external focus ring like it can be done on Mitakon lens. I had to disassemble it to figure out that DJ Optical factory engineers are using glue to secure ring firm. Fortunately that glue can be dissolved with acetone and completely removed, and in my lens copy glue is only securing one small area. I'm going to show in all details how to perform that cleaning and enabling focus ring calibration.

Disassembly steps

You will need torx screws to remove three bolts on the mount ring first.

Remove the mount ring. Next step is to check that ring is focused to infinity mark. There are two brass bars near the optical core with two black bolts on each. They are focusing helicoid guiders.

Unscrew four black bolts from brass helicoid guiders. Then focus lens to minimal 0.35m distance.

Next step needs some movement coordination. Focus lens back to infinity point, but while doing so make sure that ring with DOF scale and lens core remains in same position, only focus ring is rotating. Finally brass guiders will move up and you can remove them easier.

Make sure you memorize each brass guider position and put them to same location during assembly.

Now start slowly rotate both focus and DOF ring in CW direction, rings should stay together indicating infinity mark at DOF center. While rotating keep trying gently pull up rings. Once they release - mark that position with pencil on bottom optical core frame. It's also useful to add mark above it where focus and DOF rings remain at infinity focus marking.

Remove focus ring.

Add long pencil mark on the internal side of focus ring indicating infinity mark position. Then add three shorter marks indicating position of three small bolts on the external focus ring.

Now unscrew each bolt on focus ring, and use syringe to add few drops of acetone through that screw openings. Acetone will reach to the glue surface and soften it.

After few minutest it will be possible to accurately detach external focus ring.

Next, accurately clean out all glue from inner surface of focus ring, and outer edges of internal focus ring, but make sure you do not rotate that ring and do not wipe marks made with pencil.

Assembly steps

Once both rings are clean, attach them together by aligning long pencil mark with infinity focus and three shorter marks with location of screw openings.

Screw in all three bolts tights into focus ring. Then attach focus ring back to lens core in same marked position it was disconnected before and catch the helicoid thread then slowly rotate it in CCW direction (DOF and focus ring should remain together at infinity indicator). If you do it right, rings rotation should stop at the point shown below.

Rotate rings back until infinity is above aperture red dot. Look at the lens rear area - sockets for helicoid guiders should match their mount areas. Insert brass helicoid guiders.

Screw in all four black bolts into helicoid guiders but do not tighten them completely. First focus lens to 0.35m distance and back to infinity, and then tighten all four bolts.