Is it worth keeping Non-Ai Nikon lenses unmolested?

A 28/2? See I wouldn't bugger with a 28/2 but with a factory ring. Stop down instead but to each their own. Yeah they made roughly 40k of them. Just be aware of what exactly youre molesting
 
MacReady said:
Well, it turns out the 35mm I have is a very early one. The second type produced according to http://www.photosynthesis.co.nz/nikon/lenses.html , without bayonet screws but using 35mm instead of 3.5cm.

Oddly, it doesn't actually foul the lever at all, It's about half a mil away from even touching it.

The aperture ring is 60mm in diameter FYI.
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Those early lenses that don't have visible screws on the mount flange have f/stop rings that screw on to the barrel with rather fine threads. With some samples, it is possible to remove the screw on the side of the f/stop ring that connects it to the internal diaphragm mechanism and screw the ring on 1 or 2 turns further. This will reduce the overhang and sometimes allow it to clear the tab on some camera bodies. The facts that many body tabs are tapered and these f/stop rings are thinner also help.

The earliest of these lenses have a very deep overhang, too deep to allow this trick to work and too deep to allow them to fit any Nikkormat with a TTL meter and any of the Ai bodies that have a flip up coupling tab. The only metered bodies that they will mount on are the F and F2 Photomics. Nikon reduced the overhang when they were developing the Nikkormats.
 
Dwig said:
Those early lenses that don't have visible screws on the mount flange have f/stop rings that screw on to the barrel with rather fine threads. With some samples, it is possible to remove the screw on the side of the f/stop ring that connects it to the internal diaphragm mechanism and screw the ring on 1 or 2 turns further. This will reduce the overhang and sometimes allow it to clear the tab on some camera bodies. The facts that many body tabs are tapered and these f/stop rings are thinner also help.

The earliest of these lenses have a very deep overhang, too deep to allow this trick to work and too deep to allow them to fit any Nikkormat with a TTL meter and any of the Ai bodies that have a flip up coupling tab. The only metered bodies that they will mount on are the F and F2 Photomics. Nikon reduced the overhang when they were developing the Nikkormats.
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That's some great knowledge and something I didn't find anywhere else!

Thanks
 
Sumarongi said:
AFAIK, if one is in North America, and wants to have it done professionally, this is the address to go:

John White
1350 Folkstone Ct.
Ann Arbor MI 48105
(734) 662-1734
jwhite@aiconversions.com
http://aiconversions.com/
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I have had a total of eight Nikkors AI’d by John. Done very professionally and all turned around very quickly. And they all function perfectly on my Df. Great to deal with...

Sent from my iPad using Tapatalk
 
Dwig said:
The earliest of these lenses have a very deep overhang, too deep to allow this trick to work and too deep to allow them to fit any Nikkormat with a TTL meter and any of the Ai bodies that have a flip up coupling tab. The only metered bodies that they will mount on are the F and F2 Photomics. Nikon reduced the overhang when they were developing the Nikkormats.
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Thanks for the information. In the manual for the Df it states a number of early Nikkor's are not compatible, I thought it was some early lenses have light baffles that extend into the mirror box. I knew about the overhang but didn't realize it would be a problem on film bodies. This last week I picked up a Nikkormat FT2 from a local shop they had overhauled and painted for me. When I got it home I was having problems with the meter indexing. Ironically, the lens I left with the shop was an unmodified 2.8 cm 3.5 with a serial number below 320000. I called them to let them know that lens wasn't compatible with the camera body.
 
I still have an early Nikon F plain prism, and I still have two Nikkor lenses for it. A Nikkor 28mm f/2 ... a late copy of the Pre-AI before they were fitted with an AI aperture ring ... and a Micro-Nikkor 55mm f/3.5 Pre-AI.

The 28mm was AI'ed before I bought it. I had the 55mm AI'ed. Neither will ever be collectibles ... they were well used when I bought them although in excellent optical and functional shape for use ... so no one should ever care that they were sullied and modified from their original form.

G
 
I bought a Nikkormat and a few Nikkor lenses when I was in various places in Asia in 1972. As I recall, when I was in Japan visiting a dealer, I was informaed that the Nikkormat was construced the same as a Nikon F with the exception of the prism swap. For some reason, the Nikkormat has a top flash sync speed of 1/125 where the F is 1/90.

I still have all the lenses and camera, instructions.

Took it everywhere back then and used it until 2004 when I changed to digital.
 
madNbad said:
... I thought it was some early lenses have light baffles that extend into the mirror box. ...
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There are a few lenses from the mid-60s to early-70s where light baffles came into conflict with some Ai bodies. These included some 28mm f/3.5 and 35mm f/1.4 lens, along with some others. I used to do Ai conversions on lenses for which Nikon didn't provide kits. I could machine the rear baffle on the 28 f/3.5 to provide clearance. I've also seen some done by other shops that simply removed the baffle.

The lenses with the deep f/stop ring overhang (a dust shield) were made between 1959 and roughly 1961, or so. Nikon did provide a service to address the issue during the early 1960s. I have a 21mm f/4 that was altered, though perhaps not by Nikon.
 
CameraQuest said:
these are the early Nikon F lenses that you should never modify

- the earliest lenses made for the 1959 Nikon F

https://cameraquest.com/nftick.htm
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One aspect of these lenses derives from Nikon's paranoia when designing the F-mount. Lens mounts had common issues back in the day. Nikon wanted to avoid the problems they'd had to work around or live with. The common problems were:
  1. too small in diameter limiting lens design. LTM, Contax/NikonRF, Exakta, and others were guilty.
  2. lens mount faces would wear and/or be damaged by grit/dirt.
  3. bayonet mounts had unreliable latches.
To address #1 they made the inner diameter of the F-mount equal to the film image diagonal. To address #2 they used hard, but dissimilar metals for the body and lens flanges and used a dead bolt pin, link the Leica M, to address #3.

Additionally, they designed the lenses so that the f/stop ring overhung the mounting flange as an additional dust/dirt shield to further address #2. The original overhang on the "tick mark" lenses was something around 3mm. It covered most of the side of the body flange on the F. They reduced this to about 1.5mm in the early 60s to address issues with the meter coupling on the meter coupling of the Nikkormat FT being developed. The early tick mark lenses will only mount on the F, F2, Nikkorex F (and the Ricoh version), and Nikkormat FS unless the lens was modified.
 
If there's some special collector value, I would keep unaltered, otherwise, I would make them more useful.


With that said, is anybody still doing AI mods on lenses these days? I believe Nikon USA has been out of that business for years, if not decades. Anybody else? I have a few that *might* be worth an AI mod.
 
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