Today I’m disassembling compact manual focus Pergear 35mm F1.2 APS-C lens in Fuji X mount. Lens mechanics works smooth and I’m interested to see how it’s designed. I’d like to also check if there is a way to introduce aperture click-stops in a similar way it can be done for 7Artisans 35mm F1.2 lens.
Disassembly steps
Looks like the front lens plate of Pergear 35mm F1.2 may be holding glass under it, so I’m skipping front area exploration for now to keep the correct factory optical alignment. So starting the disassembly from the rear side. First I’m unscrewing three bolts from the mount ring.
That’s interesting – mount ring is heavy and probably is made of brass, which is good to see. Now I’m unscrewing another set of three bolts, and removing black ring.
At this point you have access to the aperture ring, and aperture ring transmission. I saw a similar design in 7Artisans 35mm F2 lens. Now accurately remove the external aperture ring.
To remove internal aperture transmission ring you need to unscrew brass bolt.
Then focus lens to infinity, and accurately take out the aperture transmission ring. During reverse assembly make sure to focus lens to infinity again and properly fit the transmission ring to the internal aperture module brass bolt.
Finally I’m partially unscrewing three small bolts on the focus ring, and it can be easily removed. As you can see Pergear engineers are using classical helicoid design, and it’s very good that inner helicoid thread surface is also anodized. This design allows easy external manual focus calibration.
There are plenty of grease in all mechanical friction areas, and I have to add that all parts are precisely machined and sit very close to each other.
From what I see it’s quite challenging to come with aperture click-stop design. Lens is very small and it’s hard to find area where a tiny ball and spring can be located. I’m planning to give it a try and probably use the aperture transmission ring for that purpose. For now I’m assembling this Pergear 35mm F1.2 back, and continue with some shooting tomorrow (if the Seattle weather is good enough).
Conclusions
Personally I’m quite satisfied to see high precision level of lens mechanics in this Pergear 35mm F1.2 lens model. Helicoid is nicely done with use of brass guiders and anodized thread surface. All parts are also all metal, thick and durable to last for a very long time. It’s very easy to open the lens and replace the grease if needed after extensive use, and I’m counting disassembly complexity level of this lens as very easy.
One minor thing noticed though – is the aperture ring rotation when lens is focused to 25cm. At one point it’s not completely smooth, and probably the aperture transmission ring sockets could be a little longer for this focus position. But ring still rotates well, I’ll anyway experiment with that over time to see how durable is that area.
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