Number of 7artisans 35mm F1.2 owners reported that infinity focus at F1.2 is not correct. During my recent review I’ve assumed that three tiny Allen (or Torx) bolts on the focus ring may serve to calibrate the infinity point.
Today I decided to check that. I’ve also realized that my sample can’t perfectly focus at infinity on the very far distance (more than 200ft). And the good news is that it can be relatively easily calibrated without disassembly or sending the lens back to the factory : )
I’m using Torx T3 screwdriver, probably T2 should better fit (update: T2 size confirmed by one of 7artisans 35mm F1.2 owner).
- Mount the lens on camera and rotate focus ring to infinity until it stops (focus ring rotation blocker inside doesn’t allow to pass the infinity mark).
- Gently unscrew all three tiny Torx bolts on the focus ring, make about 2 full turns on each. It’s important to make sure focus ring is not rotating during that procedure so keep it located at infinity point firm.
- When focus ring is loose, rotate it to “5m” mark. Front lens barrel should not move during that wich indicated you are only rotating focus ring without actually focusing.
- Gently screw back all three Torx bolts. Congratulations, now your lens can focus more far, and will pass the real infinity distance. Now make sure you set aperture to F1.2 and focus lens to perfect infinity point, it’s preferred to use very distant light source like the street lamp or star.
- The final set of steps is to gently unscrew all 3 Torx bolts to loose focus ring, then rotate the ring to “infinity” mark, and tighten 3 Torx bolts. Now my 7artisans 35mm F1.2 sample focuses perfectly at F1.2
UPDATE: here is more detailed guide with each step pictures: calibrating focus – adjustable focus ring
I love the mechanical design, 7artisans did great job making the infinity calibration so easy. The focus ring has stopper at infinity mark, so you just simply align the helicoid to proper position.
BTW, similar approach works for Mitakon 35mm F0.95 Mark II, and 7artisans 12mm F2.8 (performed on my lens samples), the only difference in steps is to use flat screwdriver.