Thoughts on Micro Nikkor 105mm f2.8

[Zang]

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.

[Birna Rørslett]

A brave man

[Zang]

A brave man

"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.

[ColinM]

Would either of you like to hazard a guess at which incarnation of the 105 2.8 this is?

[Zang]

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?

[Zang]

OK, based on Roland's chart, it's 1983-2005 batch.

[Zang]

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.

[Birna Rørslett]

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.

[Roland Vink]

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.

[Zang]

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.

[Zang]

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.

[Zang]

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.

[Zang]

The lens is very sharp!

[Zang]

Another sample from 1m.

[Zang]

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!