# Will a NON AI lens work on a Nikon D200? Read post for more details



## CamCracker (Oct 18, 2011)

I have a 50mm f/2 non ai lens, and I was wondering if it would fit on a Nikon d200. I've read before that it can't work because of the reason here from the aiconversion website:

"Unconverted lenses should not be mounted on these bodies because of the interference between the aperture ring and the sliding aperture sensing tab (at about the 2 o&#8217;clock position outside the lens mount as you face into the mirror box)."

I'm thinking it's because of the little piece on the bottom end of the lens that would break the tab on the D200, so if I unscrew the little metal piece on the lens and try to mount it on the D200, would it mount without damaging it?

Picture is included to show the little metal piece I'm talking about removing.












Here is a photo of my actual lens, as I don't think the lens I have is this exact same one. Maybe the one I have isn't a Non AI





http://imageshack.us/photo/my-images/706/d3s27691200.jpg/


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## Derrel (Oct 18, 2011)

Well, yeah, the "buckhorns" or the mechanical aperture coupling prong shown circled can hit the AI coupling ridge...but even WORSE---the entire outside of the aperture ring might be so large that it would break off the plastic minimum aperture sensing pin, located at the 7 o-clock position.

The lens shown above is one of my personal favorites, a late-run, rubber inset focusing ring version pre-AI 50mm f/2 Nikkor, which has been AI-converted. If you break off the minimum aperture sensing tab, then the camera is in really bad shape...the bottom edge of a NON-AI Nikkor might very well be a bit "fatter" than this relatively late pre-AI 50 you're showing...so, there are actually TWO critical controls you do not wish to bung up by forcing a pre-AI, non-modified lens onto a D200.


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## CamCracker (Oct 18, 2011)

Derrel said:


> Well, yeah, the "buckhorns" or the mechanical aperture coupling prong shown circled can hit the AI coupling ridge...but even WORSE---the entire outside of the aperture ring might be so large that it would break off the plastic minimum aperture sensing pin, located at the 7 o-clock position.
> 
> The lens shown above is one of my personal favorites, a late-run, rubber inset focusing ring version pre-AI 50mm f/2 Nikkor, which has been AI-converted. If you break off the minimum aperture sensing tab, then the camera is in really bad shape...the bottom edge of a NON-AI Nikkor might very well be a bit "fatter" than this relatively late pre-AI 50 you're showing...so, there are actually TWO critical controls you do not wish to bung up by forcing a pre-AI, non-modified lens onto a D200.



So by looking at the bottom picture, the back of the lens, can you tell if this is a pre ai? or not? That is the exact same lens I have, the bottom picture, not the one with the red circle. So what you're saying is that this lens I have, the bottom picture, won't work on the D200?


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## Derrel (Oct 18, 2011)

The lens you have is an un-altered pre-AI lens. The aperture coupling prong has no holes in it. I wrote my initial post before the second photo was uploaded. If yuo want to use that lens on a D200, you need to file off some metal at the top, and at the bottom, of the outside edge of the aperture control ring. Not a whole "lot" of metal...it can be done at home with a file and or Dremel tool. If you just gently lay it into the bayonet lugs on the D200, you will see how the bottom edge of the aperture control ring hits that delicate, plastic minimum aperture sensing pin at the 7 o'clock location.


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## CamCracker (Oct 18, 2011)

Derrel said:


> The lens you have is an un-altered pre-AI lens. The aperture coupling prong has no holes in it. I wrote my initial post before the second photo was uploaded. If yuo want to use that lens on a D200, you need to file off some metal at the top, and at the bottom, of the outside edge of the aperture control ring. Not a whole "lot" of metal...it can be done at home with a file and or Dremel tool. If you just gently lay it into the bayonet lugs on the D200, you will see how the bottom edge of the aperture control ring hits that delicate, plastic minimum aperture sensing pin at the 7 o'clock location.



Thank you so much for your help. I'm trying to understand where exactly you are referring to, filing some of the metal on the lens. Could you somehow show me in a picture/circle which areas to file off? It would be very much appreciated. Thank you again!


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## Derrel (Oct 18, 2011)

DIY Nikkor AI-conversion in a GOogle search, will take you to this page which shows how to do the conversion:Nikon AI conversion
See
 also  DIY Nikon AI modification

Finally THIS page shows the minimum aperture sensing pin in a red circle, and also shows how the metal; needs to be removed on an old "silver-barrel" style Nikkor

Nikkor AI Conversion | kpixel - photographs and art by young koh


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## CamCracker (Oct 18, 2011)

Wow. Thank you, this answers my question by far, and then some. Thank you so much!


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## nnhoang (Oct 18, 2011)

You have to be very careful on where to file off. You should try to search locally if a camera shop still does pre-AI to AI conversions. It involves machining down the aperture ring so that the little prong on the camera can 'connect' with the lens to know what aperture you're on. Without precise machining, you will lose metering abilities with your lens and will have to go full manual.






Where I circled (poorly ) in red, you can see that the aperture ring is smooth. This doesn't allow the camera to connect with the lens and infact can damage the camera.  
In AI lenses, the aperture ring is not smooth, but rather has 'stoppers' so the aperture index tab can 'read' what aperture you are at. Below where I circled in green is the 'stopper'





That stopper will connect with the AI tab on your camera,





If you attach your pre-AI lens to your camera, you risk the chance that your AI tab will be damaged.


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## CamCracker (Oct 18, 2011)

Wow! Thank you so much! You've educated me a lot! Thanks!


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## BAphotos (Oct 18, 2011)

I recently converted an old 135mm I picked up.  There are a few options really.  Ideally, is the first option which is finding an old Nikon produced ai-conversion kit. They're all discontinued, but a few are still floating around. You'll either have to do the conversion or have a shop do it.  This is the best option as there's no filing involved and the lens will retain it's resale value better.  Here's a site that lists the kits and has links to a few shops you can check for them:
http://www.photosynthesis.co.nz/nikon/aimod.html
Option 2 is finding a camera shop/place that does the ai-conversion.  Here's a link to a guy well known for doing them and the prices are very reasonable:
http://www.aiconversions.com/
The last option is doing it yourself.  But be aware that it's not something many will attempt.  I did it for my 135mm going into it knowing that if I screwed it up, it'd be my own fault.  Here's a link to my post about it:
http://www.thephotoforum.com/forum/...ished-ai-conversion-nikkor-q-135mm-2-8-a.html
Some tips if you do attempt the conversion yourself:  Do NOT do this with the lens together, you'll get fine metal all over and in it, also you need to have the aperture ring filed down to just below the mount ring.  Make sure you have a similar lens or find info on exactly where you need to have the groove stop so your camera can read the aperture correctly. (i.e. use the picture above of the ai version of the lens)

Hope this helps!


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## Derrel (Oct 18, 2011)

As BAphotos mentioned, for the AI-coupling, you need to ,"find info on exactly where you need to have the groove stop so your camera can read the aperture correctly. (i.e. use the picture above of the ai version of the lens)"--that information is found in the chart in the very first link I provided....the AI coupling ridge VARIES, based upon what the MAXIMUM aperture of the lens is!!!!! Now, if your lens is a an f/2 lens, then YES, the edge of the AI coupling ridge on the lens needs to be right where it is shown in the photo.


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## kshapero (Oct 27, 2011)

I have used http://www.aiconversions.com/ for years with great satisfaction.


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