Thoughts on Micro Nikkor 105mm f2.8

[Zang]

A question to anyone who has Micro Nikkor 105mm f2.8 AI-S. If you can help measure precisely the height of front element part that raises above the middle helicoid then I can easily figure out the spacing issue. Can anyone please help?

[MEPER]

Kenneth worked with the lens some years ago and made a couple of videos (Part1, Part2):

https://www.youtube.com/watch?v=lNA7G2JdDqU
https://www.youtube.com/watch?v=sgBfkfmYo7U&t=3s

But those are time laps videos and not the usual where all details/measurements are shown.
So probably not of much help. It is probably part2 if any help. I have not watched them in details.

[Birna Rørslett]

The gap measures 2.50mm on my sample of the 105AIS.

[Zang]

Kenneth worked with the lens some years ago and made a couple of videos (Part1, Part2):

https://www.youtube.com/watch?v=lNA7G2JdDqU
https://www.youtube.com/watch?v=sgBfkfmYo7U&t=3s

But those are time laps videos and not the usual where all details/measurements are shown.
So probably not of much help. It is probably part2 if any help. I have not watched them in details.

Thanks Meper. I did not find any details in the video that tell me either the thinner spacer should go to the front or back.

[MEPER]

No spacer image either on Richards page (as far as I could see):
https://richardhaw.com/2017/02/19/repair-micro-nikkor-105mm-f2-8-ai-s/

I wonder if those spacers thickness could be individual pr. lens?

[Zang]

The gap measures 2.50mm on my sample of the 105AIS.

Thank you so much Birna! I trust you did the same but I used the tip of the caliper for measurement and mine was 2.82mm. That means most likely I put the rings in wrong order. The thinner should go to the rear side and the thicker one should go to the front side. They measure 0.5 and 0.05 each so the difference seems to match.

[Zang]

No spacer image either on Richards page (as far as I could see):
https://richardhaw.com/2017/02/19/repair-micro-nikkor-105mm-f2-8-ai-s/

I wonder if those spacers thickness could be individual pr. lens?

That would be the worst for me. With mass production lens, I can't believe they did that. There is a different way to calibrate the CRC based on my assessment of the design.

[Zang]

After swapping the rings, the measurement is 2.52mm, exactly as Birna's lens has. I did nonscientific testing at MFD and f2.8 and f5.6 and to my naked eyes, the lens performs identically before and after the rings swap.

[Zang]

...I was just wondering, how that was possible. There was 0.3mm difference in the CRC relative position after I swapped the rings. How come, the test pictures were still razor sharp when I put the rings wrong? I did test the lens quickly after the swap and it was still razor sharp. Of course, I only tested the lens near MFD. I will post a couple of test photos from the same lens with the new configuration this weekend.

[Gerhard2006]

The bottom line is you got it back together again and it’s razor sharp and I have this lens and totally agree with you. It has become my favourite lens and it’s in my camera bag at all times. I even chipped it and it works great on my Z5 with my FTZ adapter. Regards Gerry

[Zang]

The bottom line is you got it back together again and it’s razor sharp and I have this lens and totally agree with you. It has become my favourite lens and it’s in my camera bag at all times. I even chipped it and it works great on my Z5 with my FTZ adapter. Regards Gerry

Thanks! The best part is, my son paid $20 for it plus D70. I got both free from him anyway. The lens looks pristine and the image quality is incredible.

[Erik Lund]

These shims usually go together to give a specific distance as a set.
The technician assembling and adjusting the lens when it is build can choose from a variety shims that together give the closest thickness to what is needed.
By having several shims you can have more options with less amount of shims.
Same technique as under the F-Mount.

[Zang]

These shims usually go together to give a specific distance as a set.
The technician assembling and adjusting the lens when it is build can choose from a variety shims that together give the closest thickness to what is needed.
By having several shims you can have more options with less amount of shims.
Same technique as under the F-Mount.

That makes sense. I asked people in several forums and it seems like the measurements were pretty close to what Birna provided. I decided to swap the rings to get close to that configuration.

Interestingly, I tested the lens before and after the swap and the image quality was nearly identical.