Nikkor 1.2 Focusing Throw

[LJSLATER]

PS

I contacted Roger Cicala, the proprietor and author of the wonderful lensrentals.com blog. He told me he might be considering publishing a tear-down of the 50mm f/1.2 AIS.

By the way Mr. Waves, I enjoyed viewing your blog. I wonder how I never came across it before?

 

[Christiaan Phleger]

Thanks, just for the true geeks.
Its the same size, so you can use that set screw.
Drinking and operating a screwdriver can be hazardous to your gear. Use caution. I speak from experience...
I've made the effort and checked my copy of a 50mm Ais, and On Mine, when you remove the optical block you can peer inside of the barrel and see the two brass 'keys'. Those have no adjustment, and if that brass wears too much and gives slop it looks as if *To Me* that those were meant to be replaced with factory original parts as part of a Nikon CLA. This is different than most MF lenses.
The reason you were on hold for 20 min is probably because nobody is bothering to answer the phone. Nikon stopped selling parts months ago to anybody.
The plan *I would do* is to add a bit of heavy Lens Helicoid Grease on both surfaces of each brass key, that may take some of slop out. Of course, this was after I was satisfied that all 4 of those screws were nice and tight. Or send it to Nikon USA.

 

[LJSLATER]

The reason you were on hold for 20 min is probably because nobody is bothering to answer the phone. Nikon stopped selling parts months ago to anybody.

*slaps forehead* I remember this. There were riots in the streets and petitions everywhere. At the time I didn't grasp the implications. They should really play an audio message if you try to call the parts department instead of just blasting ads at your face.

Thank you thank you thank you Christiaan for taking the time to help an unexperienced novice in need, I hope I haven't been too much of a nuisance. Your diagnosis jives with what I can see. It's too bad there's no way to adjust these things or to add a spacer or something. I will try as you said and add a small amount of grease.

Luke

 

[Christiaan Phleger]

Yeah, where that really hit was us geeks who like to fix rather than sending Every lens in. Sometimes you have to though, I'm pretty certain Nikon would fix the lens, they are still making this model so spares are available.

Your Welcome.

IMO this shows the minute differences between Ais and the older series. The older ones were made to have more adjustment, either during assembly or as parts wore. The Ais IMO were made to be easier and more modular in assembly and to have components swapped out as they wore, which is fine as long as Nikon still supports and works on them. What sucks is trying to find parts now. Mind you, it takes some serious hard and long term use for ANY Ais lens to show the amount of wear that I'm talking about.
BTW try ebay, some smaller shops put nikon parts on there and if you call them you can sometimes find the part. I'll see if I have the parts list for your lens and see if I can find the secret code to use...

 

[Newt_on_Swings]

Ooo secret catalog codes... Also your site is really nice, great photographs

 

[Leigh B]

...one could increase the width of the projection by screwing the screw a little deeper into the projection, thereby taking up the slop. Very clever.

That works in theory, but there are problems in practice.

You'll find very few lenses that have uniform wear along the full length of the slot, just because of differences in the users who shoot them.
Some people work mostly at close distances, others work mostly at long range, and others mostly at mid-range. Each will cause a different wear pattern.

When you tighten the screw you'll find that it binds at some subject distances, while still exhibiting slop at others.
It's possible to smooth and true up the slot with a die-sinker's file, but that's a lot of work.

- Leigh

 

[LJSLATER]

A parts list would be awesome Christiaan, thanks man.

I have no idea if this link will work:
http://www.flickr.com/photos/80071240@N04/

Despite being in my twenties, I am horrible with computers.

 

[Christiaan Phleger]

Good point Leigh, I've had one or two do that. I have found that over tightening that screw can do that, which is why way back I said in 1 hour increments. Or less, really.

Good set of photos. How much play are we talking about on this lens? Have you checked the brass keys screw tightness? Have you considered swapping the keys (not sure if same part, most likely is).

 

[LJSLATER]

The screws holding the brass keys are tight—oddly, one of the keys has (unbroken) red sealant securing its screws but the other doesn’t. But neither of the keys wiggle at all relative to the tube they are attached to.

I received a PM this morning from a fellow member who chastised and even scolded me a little. I deserved that. But he also went to great lengths to patiently explain that he felt that the helical grease in my sample is dry, which may be the cause of my woes. Additionally, he gave me a lot of useful tips and warnings. I didn’t ask permission to paste his message here, so I won’t.

Even before I received his PM, I placed an order from Micro-Tools for #30 helical grease and some proper screwdrivers. I will wait until my order arrives before I resume this project.

 

[Christiaan Phleger]

Good point. I was going to suggest since you had it apart to do a cleaning of the helicoid threads and re-lube, that will for sure help. You may also want to try and loosen the brass key that does not have the sealant, there may be a slight amount of adjustment that could be made before tightening it up again. Get at 'JIS cross-point'.

 

[LJSLATER]

Yeah, I've been researching the JIS; odd that the Japanese like to use screws that look like phillips but aren't.

I managed to find a set at WW Grainger Inc., whom I often do business with. The ones I got are made by Moody Tools, which I've heard aren't great. We'll see.

 

[Leigh B]

The difference between Phillips and cross-point is significant. It's the contour of the web, i.e. the intersection of the two flat blades set at 90°.

On a cross-point screw the web is square. On a Phillips, it's rounded and tapered. The difference is apparent when you compare heads of the two types.

All tiny cross-style screws are cross-point rather than Phillips. Using a Phillips driver on a cross-point screw will destroy the screw head.

Moody is one of the principle manufacturers of small tools; been around for many years.

- Leigh

 

[LJSLATER]

I was a little hesitant, but I decided to post an update. I have assembled and reassembled the outer-barrel so many times now, I could do it in my sleep. I received some really great instructions and advice for cleaning and regreasing the helical threads, which I followed. The focusing action was smoother afterward, but there was still “slop” or “play” when switching the direction of the focusing ring. And with the lens open, I could see that the slots and focusing keys were not mating properly—the keys jiggled back and forth with an audible clicking sound, even with a generous amount of helical grease applied to the slots that the keys travel in.

So I tried swapping the keys. There’s no play at all now, not even the tiniest bit. My lens is back together and I’m happy.


HKD_7904 by LJ Slater, on Flickr

Thanks everyone for your input and for not being too harsh on a novice who risked ruining his lens to get to the bottom of a maddeningly bothersome problem.

I still want to try the AI and pre-AI 1.2 Nikkors though….