How to get non-AI Nikkors converted?

[gryphon1911]

Andrew, it is definitely well worth the effort to get them converted.  It is not as if this three lenses are particulary unique or rare lenses. 

But why pay to have them converted - learn to modify them yourself - there are a number of examples on this site as to how it is done.  Good luck.

I think the last thing that any Nikon lens wants is my ham fisted mitts going to town on them.  I'd rather pay a bit of money and have someone with the proper skill and tools to do it.

I'll try and find the example on the site an see...but my initial thought is that I am ill equipped to do the deed. 

[Roland Vink]

Before you let anyone put a file to your aperture rings, see if there are any new old stock aperture rings still available. Some suppliers listed here: http://photosynthesis.co.nz/nikon/aimod.html#new
Aztech Services have (or had) a large range of AI conversion kits that I have not seen elsewhere.

[basker]

I hear bold claims about 3D printers. Would an AI conversion ring be a candidate for output? Since it is plastic you could call it current technology. 

[Roland Vink]

Interesting idea. Pre-AI, AI and AIS aperture rings are made from Aluminium alloy, and the tolerances are quite fine. Would a plastic replacement made with a 3D printer be strong enough and have sufficient precision? Series-E and AF lenses have plastic aperture rings, so it might be possible.

[basker]

 

...Would a plastic replacement made with a 3D printer be strong enough and have sufficient precision? Series-E and AF lenses have plastic aperture rings, so it might be possible.

In casual reading I see 100 micron tolerance claimed. The finish is not especially attractive, but there seems to be remedies for that. You would need a UV resistant plastic that is not too brittle. Seems like injection molded plastic would be better except for the tooling cost.

Modification is not that expensive or hard to find, but I am reluctant to commit the original ring.

[Hugh_3170]

No matter how the lenses are converted, the effort is well worth it, especially if one is using cameras such as the D500, Df, D8xx,  etc  that have an aperture follower tab that can engage with the ridge or tab that the conversion process provides or creates on the diaphragm /aperture ring. 

I agree that finding a factory made Ai ring that suits the lens in question is the ideal situation, but these are getting harder to find and modifying the existing ring is often the only option.

[Jack Dahlgren]

Seems like some of the online 3D printers could recreate conversion rings given an accurate 3D model.
For example shapeways prints in aluminum (along with other metals)
https://www.shapeways.com/materials/aluminum.
Anyone have an out of stock conversion ring to try?

[Bjørn Solberg]

Hi Peter in Los Alamos, sorry for late reply, but I had to wait for proper screwdriver. But here are pictures of todays Ai conversion of  55mm 3.5 - 32 Micro Nikkor - P serial 713439.

As you can see, in a sophisticated workshop, an adjusted sofaleg can really do the trick. I rinse the ring(and my hands) well in hot running water after visiting "Emil i Lönnebergas snickarboden".

I spray some black paint on a sheet of paper, and use a Q tip to put some paint on the ring after.

More questions? Just ask.

[Bjørn Rørslett]

An ingenious lens aperture ring clamp for sure

The electricity setup in that tool shed appears a little on the rickety side, though ...

[Peter]

Hey I do about the same thing, had my local machine shop mill mine for $10.00 each they managed to bend my 105mm K lens ring I had to lightly tap it with a piece of wood still a tad out of round but has not given me any issues. The Nikkor-H 85mm f1.8 came out perfect. I wanted to keep these two lenses clean looking. But for some tosser lenses I break out the hack and file and Testors model paint and shoot away.

[richardHaw]

had my local machine shop mill mine for $10.00 each they managed to bend my 105mm K lens ring

[MarcelvanEngen]

Hi all,
I was reading your post and wanted to share my way of non-AI conversions. These lenses are so nicely made. I respect the beautiful mechanics and the labor of love that went into them decades ago.
Rather than chipping / filing away all the material on the aperture ring, I just cut material on the inside of the aperture ring, starting at the points as indicated earlier in this post and as seen on Richards and others website for the right aperture measurements.
I do this with a cross table and and high speed mill. I leave around 0.6mm on the top where the rabbit ears are mounted.

The beauty of this conversion is that A: you dont see this on the outside of the Lens once mounted, B: the rabbit ears stay intact, C: it mounts perfectly on a Df and D300.

So far I have done this on a Nikon Nikkor 200mm, 100mm, 135mm.
The 50mm f1.4 needs material to be added on which I did with some black putty material that is rock hard and easy moldable.
Any questions let me know. More than willing to help out. Based in UK.
If necessary I can post more pictures.

[MarcelvanEngen]

Two other pictures of how it looks once the aperture ring is milled and how it looks once mounted back onto the lens.

[Erik Lund]

That is a nice clean look, never seen it done like that before

[Matthew Currie]

That's nice looking, but I checked a couple of lenses and it appears it would not work for all.  The later 105/2.5 would, but the 85/1.4, for example, would not.  On that one, the AI tab and the outer diameter of the ring are flush, at least on the cameras I tried it on. 

In addition, what John White refers to as the "type B" conversion, to clear the minimum aperture switch on lower-end cameras that lack an AI follower, cannot be done.  At least as far as I can see from an N65, an N-60 based Fuji S1, and a D3200, all those tabs overlap the outside diameter of the ring.  This is, of course, a non-issue for almost all cameras you're likely to use, including the later low-end models such as the D3200 in which that switch is pushed down rather than sideways, but it's a consideration if for some reason you should ever want to mount the lens on one of the older low-end cameras which include the D70, 80 and 90. 

I like the idea, though.  The only unconverted lenses I currently have are a very old 28/3.5, which is definitely out, and a couple of 50/1.4.  Maybe I'll have to try it on one of those.  It would be a grand excuse to get a rotary vise for the milling machine, wouldn't it?

edit to add:  The 28/3.5 would not convert this way, even if it were practical to take the threaded-on flange off.  The ring diameter is smaller, and the AI tab overlaps the outside. 

This is assuming that the dimensions of the AI tab are similar between an F4, a D7100 and an FM10, which are the ones I tried it on.