Mitakon Zhongyi 35mm f0.95 MK-II - aperture disassembly

[yukosteel]

Disassembly steps (updated):

 

1. unscrew inner ring with lens marking "1" CCW. Then unscrew 3 silver screws "2".

NOTE: green arrow shows scratch on metal frame inside. Actually this is "factory mark" : ) that shows calibrated position of front lens group frame. If you don't have one in your lens just mark with pencil.

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2. unscrew long black screw on the aperture ring. Pull out aperture ring.

 

3. gently pull out front lens group element.

 

4. Now you have access to aperture, and also can clean dust on glass surfaces if needed.

Remove ring that holds top aperture plate.

 

 

 

Edited March 7, 2017 by yukosteel

[yukosteel]

Here is how front lens group element looks on the other side

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6. Remove radial spring and top aperture plate.

 

7. Now you have access to aperture blades

[yukosteel]

Few more comments for this disassembly.

 

There is knocking sound when the lens is shaken with fully open aperture. Now it's pretty clear that noise is produced by that 9 aperture blades moving on their positions. That extra space is required to let all blades close to small f16 hole without extra pressure on blades metal.

 

It's also relatively easy to disassemble front area to repair aperture if any blade comes out of its place, or for cleaning internal dust.

Most of the dust may come to that area from the side hole of inner cylinder where aperture ring long screw is controlling aperture slider.

Due to front lens group is firmly assembled to metal frame, there are no risk of optical misalignment, though you need to mark it's radial position before pulling out lens group.

 

I'm also thinking on few possible options to introduce "aperture clicks" for this lens, or at least slightly increase tension of aperture ring rotation.

[Aswald]

Thanks for sharing. Rather simple construction and that circlip!  

 

I guess, the tolerance is needed for the aperture diaphragm to work easily.

[yukosteel]

I'm still in design phase of aperture clicks upgrade. Also ordered silver version of this lens, so will most likely do that on second lens.

 

If I understand right the exact half-stop clicks can be found by direct measurement of aperture hole diameter.

[Aswald]

Interesting to see your project come to fruition. I'm following. Thanks.