How to get non-AI Nikkors converted?

[Tom Gresham]

I wasn't sure where to put this, so I'll just toss it in here.  I have a couple of older Nikkor lenses which are not AI. 

I'm looking for a recommendation on where to send them to get them converted.

Thanks.

[charlie]

I've sent a few lenses to John White at http://www.aiconversions.com/ with good success.
 

[Tom Gresham]

Thanks, Charlie.  Will do.

[Bjørn Rørslett]

I anchor a thread with member experiences of converting the old Nikkors of the days before Nikon introduced the AI (Aperture Indexing) feature.

The purpose of such modification is to allow old Nikkors to be used on newer cameras. In order to effectuate this, either the aperture ring itself can be upgraded to an AI-compliant version, or modified  by removing parts of it to allow the lens to mount on these cameras. Upgrade kits are usually long out of stock for most lenses, thus the trimming and milling of the existing aperture ring tend to be required and for this task, special service facilities can be consulted.

[Roland Vink]

I have a web page with information on AI conversions: http://www.photosynthesis.co.nz/nikon/aimod.html
It gives a bit of history and a full list of AI conversion rings that Nikon had. Most are sold out long ago but some are still available on ebay and other places - my site has a few links to sellers that I know of. If you can get original rings that is the preferred option, it looks much better and you can be sure the AI ridge is in the correct place. Where original AI conversion kits are no longer available I also list some people who will do conversions by milling the original aperture ring.

If you find any errors or have new information, please let me know.

[Seapy]

When I got my first D200 2006? I fitted my Nikkor 105mm f2.5.  I didn't realise they you DON'T fit non AI lenses to most Nikon DSLR's.  It was OK on my D1 but it jammed onto the D200, I very gingerly managed to get it off again and researched the issue.

Cut a long story short, I found some websites with the info and set about the prized Nikkor with my file (I didn't have a Dremel then).  The only really crucial thing, apart from making the gap long enough is to finish the right hand side of the gap at exactly the right place.  Depending on the maximum aperture the location of the end of the gap varies.  I found a chart which gives the data, I will try to find it again.

This is my rather rough and ready result it works well enough, I found the left hand end of the gap was a bit tight to get the lens on and off so I widened it a bit later.  I had neither a vice nor a bench.  It was done at my desk with a little riffer file, I didn't bother with the rabbits ears, they are in my desk somewhere.

For this lens according to the charts I found, the right hand end of the gap has to be at f11 1/3, as I have indicated.

[Bill De Jager]

[Oops! I was thinking of chipping lenses.  They also do AI conversions but I have not tried that service.]

In the U.S., Legacy2Digital.com (http://legacy2digital.com/nikon/) is one option.  I purchased an already converted 50-135/3.5 AIS from them several years ago and was very pleased.

[Hugh_3170]

If doing the modification yourself using a Dremel (or similar equipment, e.g. the rather nice German made Proxxon), then do yourself and the lens a great big favour and DO GET yourself the matching drilling stand and table plus a suitable miniature end milling bit. 

In this way the height of the Dremel in relation to the table can be locked and stay fixed and this enables a slot of uniform depth to be gradually milled out.  I suggest about three to four cuts, each taking only about 0.25mm of metal out.  Mill out the ends of the slot as separate cuts, taking great care to get them in the correct place.  With care, a very neat slot can be cut.  Follow Seapy's advice as to exactly where the slot has to end for YOUR particular lens. 

Sorry if this is all old hat to seasoned Dremel users and afficionados.

[Seapy]

Here are my links to AI conversion info.  They may break in the future, I have used them since 2007, so it could be prudent to save the pages to your own hard drive so a copy exists, not wishing to infringe on copyright  but some of these links can be priceless and may disappear one day.

http://www.chr-breitkopf.de/photo/aiconv.en.html#ai_pos

This table is copyright of © 2015 Christoph Brieitkopf  and can be found in the above website. I reproduce it simply because it needs preserving and be available to those who need it. This is the only list of it's kind I am aware of.


http://www.aiconversions.com/compatibilitytable.htm

And from Rowlands site:
http://www.photosynthesis.co.nz/nikon/aimod.html

Of the six links I had in my AI  conversion Tech Info bookmarks only two are still live.

[Erik Lund]

When I got my first D200 2006? I fitted my Nikkor 105mm f2.5.  I didn't realise they you DON'T fit non AI lenses to most Nikon DSLR's.  It was OK on my D1 but it jammed onto the D200, I very gingerly managed to get it off again and researched the issue.

Cut a long story short, I found some websites with the info and set about the prized Nikkor with my file (I didn't have a Dremel then).  The only really crucial thing, apart from making the gap long enough is to finish the right hand side of the gap at exactly the right place.  Depending on the maximum aperture the location of the end of the gap varies.  I found a chart which gives the data, I will try to find it again.

This is my rather rough and ready result it works well enough, I found the left hand end of the gap was a bit tight to get the lens on and off so I widened it a bit later.  I had neither a vice nor a bench.  It was done at my desk with a little riffer file, I didn't bother with the rabbits ears, they are in my desk somewhere.

For this lens according to the charts I found, the right hand end of the gap has to be at f11 1/3, as I have indicated.

For the Aperture ring to work on cameras with 'Minimum Aperture sensor' like on D200 and D40 etc. you also need to cut down the aperture ring to make a second ridge for that to work properly.
The sensor informs the camera that the lens is set to minimum apeture or not... Used for P and S Mode.

If you install one of Bjørns G-Type CPUs no ridges are needed, Since G-Type lenses has no ridges... Not always a good solution since the pre Ai apertures are not always linear - But not all lenses know that...

IMHO the image show how to make a quick and dirty DIY hack that works on some cameras - Not recommended!

Some Pre-Ai aperture rings are a bit short for these mods to work like a real AI or Ais ring, they barely catch the aperture index lever on the camera, so a little extra care when mounting the lens will prolong the cameras aperture index levers life, it's a rather fragile componenet...

[Bjørn Rørslett]

At the very least, the leading edge on the aperture ring must be cut perfectly straight and normal to the ring, otherwise the metering will tend to be imprecise and/or excessive wear results.

A DIY conversion is better than none (unless you use the Df which can handle almost all non-AI lenses). However, for best results to a lens you intend to use frequently, do get it professionally modified. Or grind down the entire perimeter of the aperture ring and install a "G"-type CPU.Erik has done the latter on a few of my old pre-AI Nikkors, amongst them the original 35/3.5 PC-Nikkor from the '60s.

[Seapy]

Thanks for the clarification Eric.  I don't pretend to be a lens expert, I just did what I need to do to make his lens usable on the D200, it's one of my favourite lenses.  In due course I do intend to chip it but my funds are limited. 

I better not tell you what I plan for my Schneider 210mm...   

EDIT:
Having re-read your post Eric. it seems I am OK...  I never use Professional or Scientific modes, only Muddle and Amateur. 

[Erik Lund]

Not many things scare me re lens modifications - so bring on your Schneider project 

[Seapy]

Not many things scare me re lens modifications - so bring on your Schneider project 

   Working on it...  given we seem to be in a mail free world now, I am running out of backs of envelopes, and I don't smoke, so no fag packets to draw on.

What I would like is a helix extension tube.  I need to mount the lens ~250mm from the body flange to get down to 500mm (subject to lens). I have ideas... But this is straying OT. I will post in my Schneider thread later.

http://nikongear.net/revival/index.php/topic,2637.0.html

[David H. Hartman]

IMHO the image show how to make a quick and dirty DIY hack that works on some cameras - Not recommended!

I ground down one side of a 1/4" square file so I could file in only one direction at a time. Because of this I was able to make a much neater cut than shown above. I did this to a 105/2.5 Nikkor-P.C. I had a 105/2.5 AI and AIS to compare to. The modification worked fine. That said I did not like the process. There is a lot of chance for error. Having done it once and having succeeded I have never done it again and I don't recommend it.

If the lens is a classic in "classic" condition I'd leave it be out of respect for the lens. The Nikon Df can use most of these old non-AI lens so that's the rout I'd take. If it's a work lens, optically fine but worn otherwise I'd have someone who knows how to do it and guaranties their work do the modification.

That's my 2 cents,

Dave Hartman