How to get non-AI Nikkors converted?

[Erik Lund]

A needle file is the right tool for the finishing strokes They come in all shapes one of them is with no tooth on the side,,

The procedure for DIY using hand tools I use is:

Measure twice and cut once,,, Calipers and your eye and a sharp distinct cutting line and angle,,,

First use a hack saw if needed to remove big pieces,,, fine tooth blade for thin items tpi 24 or 32 - bimetal ones are now not so expensive,,,

Then use a quick running small power tool like Dremel the Greman Proxxon makes some amazing ones as well, I have both and the expensive proxxon is a better tool,,,

The trick is to use your eye no and with the Needle file get closer and closer to the line, when ever the little teeth gets filled up you turn the file on the side and tap it gently on the vise to whip off the tiny metal flakes so they don't scratch the surface your working on, switch angle 90 degrees from time to time ,,,

Now cleaning, water and soap before drying - don't remember to clean your hands as well,,,

Now test fitting can begin again use your eye,,,

Then continue, file, clean, test, file, clean, test and have fun!

[Tom Gresham]

After reading this, I'm reconsidering this option.  I have a 55mm f/1.2 Nikkor, but I think I'll just leave it as decoration on a Nikon F body on display.  I have a good 55mm f/1.4 manual focus lens that I can use.  Thanks for the help.

[Erik Lund]

A hack saw is of course not needed here for just an aperture ring Don't be scared I just wanted to write up a general how to DIY guide!

[pluton]

Any decent local camera repair shop should be able to properly cut the notch in a non-Ai lens for reasonable money.

[Erik Lund]

Just a small information re the aperture ring, the ridge you grind away is actually deeper than the F-Mount to avoid hard contact between the parts.

[richardHaw]

After reading this, I'm reconsidering this option.  I have a 55mm f/1.2 Nikkor, but I think I'll just leave it as decoration on a Nikon F body on display.  I have a good 55mm f/1.4 manual focus lens that I can use.  Thanks for the help.

Tom, I am going to share how I get even results with a dremel and a stand. it does not take a lot of skill, just patience and a steady hand. 

http://richardhaw.com/2016/01/21/diy-ai-conversion/

now, this will only take into consideration modern Nikon bodies with no minimum aperture sensor because I do not have to deal with them a lot of people don't as well but if you want to, you can use the same technique to shave that bit off to make a smaller tab on the aperture ring. you can use the money that you save from doing it yourself to buy an old inexpensive lens to test on. a file would work as well but the results that i get from the dremel is better.

and yes, just like mentioned above you would want to trim past the bayonet mount by 0.25 of a mm or risk compressing that tiny aperture tab. these aperture tabs come in different heights as well. my D7200's aperture tab is probably 0.15mm taller than what my D750 has! i know that it is insignificant but when doing stuff like this, you want to be sure.

Mr. Vink's site is excellent! i think that we all owe him a pint or two! i would like to treat him to a delicious bowl of ramen when he's in town.

[Danulon]

For someone who is all thumbs: is there anybody offering to do pre-ai to ai-conversions for old nikkors - preferably in Austria/ Germany?


There is still this old lense set of my father's awaiting conversion in order to be usable with modern DSLRs other than the Df.


Thanks in advance for your help!

[Hugh_3170]

Richard, the link in your useful conversion article contains a table as to where the Ai Coupling Ridge is to be placed as a function of a len's maximum aperture.  Many of the quoted positions in the table within this link are about 1/6th of a stop out.

This link from Christoph Breitkopf ( http://www.chr-breitkopf.de/photo/aiconv.en.html ), gives a table where the positions correspond exactly with those on Nikon factory aperture rings.  I know that 1/6th of a stop is not a lot, but if people are going to the effort of doing an Ai conversion, then getting the Ridge in the correct position does not represent any extra effort.

Christoph's table is here:


Position of the AI coupling ridge

The AI coupling ridge is positioned 4 2/3 aperture stops from the starting aperture, except on lenses with a starting aperture of 1.2 to 1.8. On these fast lenses the offset is 5 aperture stops.

Lens Maximum Aperture, with its Ai coupling ridge placement at aperture:

1.2    5.6 + 2/3
1.4    8
1.8    8 + 2/3
2.0    8 + 2/3
2.5    11 + 1/3
2.8    11 + 2/3
3.3    16 + 1/6
3.5    16 + 1/3
4.0    16 + 2/3
4.5    22
5.6    22 + 2/3

For example, the ridge for a lens with a maximum aperture of f/1.4, is to be placed exactly opposite f/8.0 .   Likewise, a lens with a maximum aperture of f/2.5, should have its ridge placed opposite f/(11 + 1/3) and so on.

Tom, I am going to share how I get even results with a dremel and a stand. it does not take a lot of skill, just patience and a steady hand. 

http://richardhaw.com/2016/01/21/diy-ai-conversion/

now, this will only take into consideration modern Nikon bodies with no minimum aperture sensor because I do not have to deal with them a lot of people don't as well but if you want to, you can use the same technique to shave that bit off to make a smaller tab on the aperture ring. you can use the money that you save from doing it yourself to buy an old inexpensive lens to test on. a file would work as well but the results that i get from the dremel is better.

and yes, just like mentioned above you would want to trim past the bayonet mount by 0.25 of a mm or risk compressing that tiny aperture tab. these aperture tabs come in different heights as well. my D7200's aperture tab is probably 0.15mm taller than what my D750 has! i know that it is insignificant but when doing stuff like this, you want to be sure.

Mr. Vink's site is excellent! i think that we all owe him a pint or two! i would like to treat him to a delicious bowl of ramen when he's in town.

[richardHaw]

Richard, the link in your useful conversion article contains a table as to where the Ai Coupling Ridge is to be placed as a function of a len's maximum aperture.  Many of the quoted positions in the table within this link are about 1/6th of a stop out.

This link from Christoph Breitkopf ( http://www.chr-breitkopf.de/photo/aiconv.en.html ), gives a table where the positions correspond exactly with those on Nikon factory aperture rings.  I know that 1/6th of a stop is not a lot, but if people are going to the effort of doing an Ai conversion, then getting the Ridge in the correct position does not represent any extra effort.

Christoph's table is here:


Position of the AI coupling ridge

The AI coupling ridge is positioned 4 2/3 aperture stops from the starting aperture, except on lenses with a starting aperture of 1.2 to 1.8. On these fast lenses the offset is 5 aperture stops.

Lens Maximum Aperture, with its Ai coupling ridge placement at aperture:

1.2    5.6 + 2/3
1.4    8
1.8    8 + 2/3
2.0    8 + 2/3
2.5    11 + 1/3
2.8    11 + 2/3
3.3    16 + 1/6
3.5    16 + 1/3
4.0    16 + 2/3
4.5    22
5.6    22 + 2/3

For example, the ridge for a lens with a maximum aperture of f/1.4, is to be placed exactly opposite f/8.0 .   Likewise, a lens with a maximum aperture of f/2.5, should have its ridge placed opposite f/(11 + 1/3) and so on.

thank you, hugh!!! i shall fix that as soon as possible (maybe tonight).
i shall update my blog about adding the tiny ridge for D80 type cameras. i did not add that since i was only thinking about the cameras that i have. i think it was erik who pointed that out. that thing left my mind as soon as i got my D700 which is a long time ago

[Erik Lund]

Here is a shot of a 105mm 2.5 that has been cut to Ai just for reference

[DougB]

To the OP:
I see you are in the USA, so you could use John White at AI Conversions.
He's in Ann Arbor MI & I have used him for several Ai conversions.
A great guy & you can em him with any questions
Last time I used him the cost was $25.00 or $30.00

[Erik Lund]

Please post a picture of his work, thanks.

[Michael Erlewine]

To the OP:
I see you are in the USA, so you could use John White at AI Conversions.
He's in Ann Arbor MI & I have used him for several Ai conversions.
A great guy & you can em him with any questions
Last time I used him the cost was $25.00 or $30.00

Yes, I have used John White for converting many lenses and he lives right here in Michigan, so I highly recommend him. And quick too.

[Peter]

I have done my own hack's it's easy but in one case my first lens I did I wasn't paying attention to the location for where the tab stop should be at. Example my Nikkor-P 105 2.5.
Photo at bottom, had to devise a tab and super glued it on (TRUE HACK).
I also had my local machine shop mill my Nikkor-K 105mm and my Nikkor-H 85mm for $14.00 as I wanted them to be a cleaner cut.

[RonVol]

A friend in the Netherlands sent me these images of a 105mm f/2.5 that he purchased.
It by-far has one of the most elegant solutions to this problem that I've seen so-far.
As a machinist; I can say without a doubt that this is 1st class work.

Images are by Oscar Hoogendoorn.
http://www.oscars-collection.nl/