Hello!
I recently acquired a Super Takumar 55/1.8. It's very well preserved, smooth focus, no oil on the blades. Although I can't get it to focus to infinity. I'm using it on a Sony A5100 with a M42 adapter. I know when it comes to such problems adapters are usually to blame, but I have a set of other M42 lenses that all focus to infinity without a problem and with no prior adjustments.
First I thought it was just that my focusing ring was not properly adjusted, so I followed this guide:
Shooting with a Pentax K10D: Fixing the infinite focus on a Super Takumar 24mm ... . I had no luck adjusting the focusing ring. Even if I removed the focusing ring and rotated the focus as farthest to infinity as I was able to get it, it still didn't achieve infinity focus. I unscrewed the helicodial and played with different setups of the two helicodial parts, no luck with that either, it would just stop before reaching infinity. I then unscrewed the 3 little screws that are holding the optics block attached to the helicodial and removed the optics. I could then see that the part that held the optics couldn't go any further back into the lens because it hit the aperture lever mechanism. I read this guide aswell:
https://www.pentaxforums.com/forums/114-maintenance-repair-articles/217082-ta...egreasing.html trying to find some answers why this was happening. I still have no clue, I'm beginning to think that the lenses themselves might not be properly set up, but I don't want to rush into dissasembling the optics itself. Another thing I tried was taking out the middle helicodial part and just sliding in the optics on the two rails as far back as it would go until it hit the aperture mechanism, same result as before, almost at infinity but not quite. I believe the lens also comes flush with the adapter since I filed down the aperture pin so it comes flush with the lens body. Is there something else I could attempt to do? Thank you.