NikonGear'23

Gear Talk => Lens Talk => Topic started by: Zang on December 21, 2022, 02:15:25

Title: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 21, 2022, 02:15:25
I've never had the lens before. My son brought me one from California where he bought it for cheap as a junk and used it on D70 body as a display item in his apartment. The lens is unusable. The focus ring is not turning and both sides of it are covered in dust and dirt so I took it apart. I can say that the lens is not for beginner, but if you take time to understand it, overhauling should be straight forward. Despite being faulty and dirty, I found all the parts in immaculate condition. I cannot wait to finish it and see how it performs.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Birna Rørslett on December 21, 2022, 11:32:07
A brave man :)
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 21, 2022, 13:49:34
A brave man :)

:D "Breaking" into lenses is addictive, Birna. Besides, I have only $40 to loose.

And now, I cannot help with my 'laziness'. I made no notes! I did file a small screwdriver into a small scalp to make sharp and precise marking on the internal parts. I do have vivid visual memory but it is pretty short live. My memory lasts only a couple of days before I start mixing stuffs up so I usually try to finish my job the same day. This time, my son was so excited that he asked me to record a video of putting things back. I need to wait another day to adapt a power adapter to my LED flash light to turn it to a video light. Today will be big test for my memory.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: ColinM on December 21, 2022, 19:11:20
Would either of you like to hazard a guess at which incarnation of the 105 2.8 this is?
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 21, 2022, 19:30:46
Would either of you like to hazard a guess at which incarnation of the 105 2.8 this is?

I have no idea. How can I check?
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 21, 2022, 19:34:19
OK, based on Roland's chart, it's 1983-2005 batch.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 22, 2022, 14:53:00
I assembled the lens back last night. Now I can focus the lens what was previously impossible. However, focusing is not as smooth as I would expect. It is not too bad but it is not consistent and I feel some metal grinding somewhere inside. Now, when matching the helicoids I tested each set and they moved pretty smoothly when tested individually. As the whole, the lens's focusing is not smooth. I tried my best to align the keys (both main ones and CRC ones) and I do not think they are the issue. Can anyone who have the lens please report how focusing works out of the box? Thanks.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Birna Rørslett on December 22, 2022, 18:17:34
Focusing ought to be pretty smooth. However, it is quite common for this design to develop sticky focusing. If the lens isn't used for a longer period of time, the focusing might be very hard or stuck entirely. Erik had to relubricate my 105/2.8 AIS after such an incident.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Roland Vink on December 22, 2022, 18:18:35
Hi Zang, I have a copy of the AIS 105/2.8 micro. I bought it in near new condition from eBay some years ago. The focus ring is well damped and a little heavier than non-macro lenses, which is normal for a lens with such long focus helicoids. The focus action is fairly smooth and even from infinity to close and back. However, I have other lenses which are smoother - on my copy there is occasionally hint of roughness as if there is some dirt in the helicoids, but mostly it is smooth. The lens has a small thumb screw on the side which increases the damping on the focus ring to prevent focus creep if the lens is pointed straight down (it does not lock it completely like the one on the AIS 105/4 micro). Check that it has not been screwed down as it could affect the smoothness of the focus ring.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 22, 2022, 21:36:22
Focusing ought to be pretty smooth. However, it is quite common for this design to develop sticky focusing. If the lens isn't used for a longer period of time, the focusing might be very hard or stuck entirely. Erik had to relubricate my 105/2.8 AIS after such an incident.

Thank you Birna for your feedback regarding the lens. Mine was completely stuck. I overhauled it completely but am not satisfied with the focusing experience after the fix. I will revisit it again.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 22, 2022, 21:39:25
Hi Zang, I have a copy of the AIS 105/2.8 micro. I bought it in near new condition from eBay some years ago. The focus ring is well damped and a little heavier than non-macro lenses, which is normal for a lens with such long focus helicoids. The focus action is fairly smooth and even from infinity to close and back. However, I have other lenses which are smoother - on my copy there is occasionally hint of roughness as if there is some dirt in the helicoids, but mostly it is smooth. The lens has a small thumb screw on the side which increases the damping on the focus ring to prevent focus creep if the lens is pointed straight down (it does not lock it completely like the one on the AIS 105/4 micro). Check that it has not been screwed down as it could affect the smoothness of the focus ring.

Thank you Roland for your feedback. That is not the locking screw. The lens is operational but focusing feels rough and I already have overhauled it. I put very minimal grease everywhere, though. The movement feels dry and uneven. I will try testing each moving part to find out the issue.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 23, 2022, 03:31:17
Good news and bad news... The good news is, I have found and fixed the issue with the lens. The bad news is... me aging. I completely forgot putting grease to the internal helicoid and the corresponding face of the middle helicoid. After I disassembled the lens the second time, I found metal powder on the threads :( Hopefully it did not affect the lens too bad. Now, the lens is back in one piece again and it is fairly smooth. Its behavior is exactly as described by Birna and Roland.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 23, 2022, 06:29:01
The lens is very sharp!
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 23, 2022, 07:30:30
Another sample from 1m.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 25, 2022, 03:12:22
Actually, one thing I was not sure about. There were two brass rings sitting on both side of the CRC barrel as shown in the picture. One of them is thicker and one of them is thinner. I put the thicker to the back of the barrel and the thinner to the front side of the barrel. Now, thinking again, I don't think I am sure if that was the correct order. I doubt you guys know or remember but if anyone who had a chance working on this lens (Richard?) and remember those rings and tell me their order I would be very appreciated!
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 25, 2022, 05:07:58
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? :)
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: MEPER on December 25, 2022, 12:51:07
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=lNA7G2JdDqU)
https://www.youtube.com/watch?v=sgBfkfmYo7U&t=3s (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.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Birna Rørslett on December 25, 2022, 14:58:10
The gap measures 2.50mm on my sample of the 105AIS.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 25, 2022, 16:13:52
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=lNA7G2JdDqU)
https://www.youtube.com/watch?v=sgBfkfmYo7U&t=3s (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.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: MEPER on December 25, 2022, 16:23:18
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/ (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?
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 25, 2022, 17:02:19
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.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 25, 2022, 17:06:19
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/ (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.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 25, 2022, 19:49:43
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.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on December 31, 2022, 06:03:14
...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.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Gerhard2006 on January 18, 2023, 06:58:25
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
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on January 22, 2023, 17:11:51
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.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Erik Lund on February 07, 2023, 13:32:10
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.
Title: Re: Thoughts on Micro Nikkor 105mm f2.8
Post by: Zang on February 07, 2023, 14:19:22
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.