Disassembly – Mitakon ZhongYi 50mm F0.95 mark II “Dark Knight” lens

This article covers disassembly of rear lens area to access aperture blades and rear glass elements of Mitakon Zhongy\Yi 50mm F0.95 Speedmaster. If you are looking just for the focus calibration – try this focus calibration guide instead.

Disassembly steps

First disassembly step is very simple – unscrew three mount bolts.

Remove mount ring.

Then remove black ring with DOF scale.

What a surprise! There is second part of the mount ring made of thick aluminum. Unscrew three bolts and remove it.

For the next step a spanning wrench is required. Unscrew CCW whole rear glass module, it will take about 9-10 full turns.

At this point you can clean inner glass surface and aperture blades if needed.

Mitakon ZhongYi 50mm F0.95 MK-II has same helicoid focuser design like another smaller Speedmasters: 35mm F095 and 25mm F0.95.

I decided to also check the glass of the rear module. Rear metal ring can be unscrewed CCW while holding main module case with spanning wrench placed inside lens body.

Now the rear glass piece can be pulled out.

And here is another lens group. It’s interesting to see that glass sides are not completely blackened, though it should not significantly affect lens performance.

I’ve also tried to disassemble the front area. There is quite simple technique of removing front ring with letters. I’m attaching thick adhesive tape to the lettered ring in many places, than using Sony-E mount lens rear cap edges to capture that tape and just unscrewing CCW that ring.

Unlike the Mitakon 35mm F0.95 Speedmaster, this “Dark Knight” is more securely built in the front area, and I can see some glue applications around the front lens module. There are no real need to disassemble it today, so I’m ending up disassembly at this point.

I’ve assembled lens in reverse order and compared optical results. Looks like glass mount tolerance is quite high, because reassembly didn’t affect optical performance. The lens takes sharp pictures with decent level of details in center and borders with Sony A7s.