Non Ai lens??

I currently have a D750 and was wondering about using non-AI lens on that body. I've read and heard that there can be damage but I'm not sure I fully understand exactly what the damage would be. I don't want to damage anything, but I do still have several non-AI lens that are extremely good quality. If there is a chance of damage, is there a way to prevent it and still use these old lens?

I don't have any non-ai lenses to see for myself, but from what I understand, the contacts and a tab on the camera mount that can be squished because the lens does not have cutouts that came in future lenses.
Found this on quick search:
https://www.youtube.com/watch?v=i8y9dlgJZS0
He mentions getting his lens modified. Maybe somebody here has had that done.

edit:
Found this, with some better pictures. Looks like its not the contacts as I thought above. Interesting.
Will a NON AI lens work on a Nikon D200? Read post for more details | Photography Forum
Also some links in there to do-it-yourself filing. [yikes]

Right, modification of non-AI lenses to be AI is the recommended method. Back in the day, when AI first came out, Nikon offered to modify any non-AI lens to be AI for a minor fee. There are still places that will do it for many lenses.
nikon ai modification - Google Search

So, if I modified the non-AI lens with the cut groove, does the camera actually use any information that is determined by the location of the aperture ring? Or is the modification just to give clearance to the tab on the camera? If that is the case, would it hurt to just trim down the whole ring, all around??

Nikon Ai Conversions

Here's a link to a full explanation... including a list of lenses and their respective serial numbers... You might need to compare your specific lenses to this list for a clear answer. Some non-AI lenses simply could not be converted...

Jim_Y said:

So, if I modified the non-AI lens with the cut groove, does the camera actually use any information that is determined by the location of the aperture ring? Or is the modification just to give clearance to the tab on the camera? If that is the case, would it hurt to just trim down the whole ring, all around??

Click to expand...

You just need to make sure that you can mount it without hitting the aperture reading tab and that you cut out/grow on a tab at the right area on the aperture scale that the camera's tab will then read based on the aperture ring's/camera tab's position vs what you set the max ap to be in the menu.

FredKingston said:

Nikon Ai Conversions

Here's a link to a full explanation... including a list of lenses and their respective serial numbers... You might need to compare your specific lenses to this list for a clear answer. Some non-AI lenses simply could not be converted...

Click to expand...

Either if the rear protruded too much or if the the lens was too narrow, there really isn't an easy way to grow a piece of aluminum on to catch the camera's tab. I've tried with my 50/2 and it was simply too narrow. Bolting something on would work, but it's a tad more gimmicky than cutting out an area at the right place.

And of course things like the 50/1.2 can never get a 3rd party distance chip is due to the sheer diameter of the rear element.