How to distinguish pre-AI Nikon lenses?

[Lena]

Help needed

Some ebay sellers do not include markings like Ai/AiS and non-AI in the descriptions.
I know pre-Ai lenses won't mount on my Nikon, but sometimes I just don't know what I'm looking at...

Is this one pre-Ai, for example? How to distinguish them?
http://www.ebay.co.uk/itm/Nikon-Nikkor-24mm-f2-8-wide-angle-lens-/150820236424?pt=UK_Lenses_Filters_Lenses&hash=item231d962c88

[sichko]

This one is Ais.

If you have the serial number you can use the photosynthesis site.

[Nesster]

I was going to send you to Ken Rockwell but Rick Oleson to the rescue
http://rick_oleson.tripod.com/index-153.html
Or Nikon themselves
http://support.nikonusa.com/app/answers/detail/a_id/5366/~/what-is-the-difference-between-an-ai-lens,-an-ai-s-lens,-and-non-ai-lens%3F


that 24mm for sale is Ais

[fotomachi]

Perhaps this reading can help you. And this image can help you distinguish an Ai-modified lens from the rest.

[sichko]

What's wrong with Ken Rockwell's site ?

[mdarnton]

Some of the sources people have linked to are not quite correct. The essential difference--the one that matters the most--is whether or not the back of the aperture ring is a whole uncut surface (non-AI) or whether it's been cut back in several steps to allow clearance for the little tab that sticks out forward from the side of the lens mount at about 2:00 when there is no lens mounted. If there is no space on the back of the lens aperture ring for that tab to sit in without forceful interference, don't mount the lens. On some cameras there's another projection from the mount at 8:00 that senses when the lens has been set to its smallest aperture, and if so the appropriate cutting for that should be on the back of the aperture ring, also.

All of the stuff about rabbit ears having holes, double aperture stop scales, etc, will not actually tell you if a lens will mount properly and function--it has to do with Nikon's own way of making the original AI lenses, but it doesn't cover all of the possible ways to modify a lens later that various people have come up with or done at home.

The single most important issue is whether you're going to bend or break off that tab at 2:00 on the mount it you put on a lens.

All of the stuff about metering and nostrils in rabbit ears is nice to consider, but the most important thing is whether you're going to break your camera by mounting a specific lens. If you aren't, then the other stuff can be got around.

[Lena]

Thanks a lot!

[Lena]

There are some Helios or Mir lenses available in Nikon mount. Is it pre-Ai?

[NikonD]

If the aperture ring has a ridge bellow aperture numbers than it's AI/AI-S otherwise its non-AI/pre-AI and has to be modified

[Gurdie]

AFAIK, all Nikon-mount Russian made lenses are AI and can be mounted on all Nikon DSLRs, but only bodies from D200 upwards allow exposure metering.

[sichko]

[Lena]

I googled a bit on that and found this site
http://radojuva.com.ua/2012/03/review-lens-helios-81n-2-50mm/

If the author is right, Helios 81 lenses came in both pre-Ai and Ai mounts. Arsats are newer, so probably they would be Ai.