forjava Loc: Half Moon Bay, CA

I have 3 non-AI lenses: a 50mm f/2 H, a 50mm f/1.4 S, and a 135mm f/3.5 Q.
The f/2 does not seat in my D3100 or in my N6006, as it should.
That is the problem.

The f/1.4 and f/3.5 seat in my D3100, and in my N6006, as they should.
So, the f/2 lens almost seats but actually it does not.
The edge of each camera body's metal mount is quite visible from the side with the f/2 but is largely covered with the f/1.4 and the f/3.5.
The barrels of the f/1.4 and f/3.5 lenses get closer to the camera body than does the f/2.

Using a caliper, I measure the inner diameter of the f/2 lens barrel at the metal mount.
This metric is smaller in diameter than the diameters of the other two lenses.

Most of the f/2 lenses on eBay have metal mounts with five screws, like my f/1.4 and f/3.5.
My f/2, like a couple of others on eBay has a mount designed without visible screws.

Is the f/2 issue normal and expected? Fixable?
TiA for your expertise.

lamiaceae Loc: San Luis Obispo County, CA

pictures might help (especially for those of us with out the exact same equipment -- but who would like to understand and learn).

Dngallagher Loc: Wilmington De.

Have you looked at sites like this and Nikon directly for information?

http://www.kenrockwell.com/nikon/50mm-f2.htm

RWR Loc: La Mesa, CA

Your 50mm f/2.0 H is one of the first Nikon F mount lenses, which have no screws. The 50mm f/1.4 S and 135mm f/3.5 Q with screws are later versions. If they mount easily, they have been properly AI modified (part of the rear rim of the aperture ring has been cut away). You can do a Google search for information on how to modify the 50 f/2.0.

Bobspez Loc: Southern NJ, USA

The D3100 does not need to have the non-ai lenses modified.in order to mount. The d3100 to 3300, the D5000 to 5500,The D40(x) and the D60 will mount these non modified non-ai lenses with no problem.
http://www.kenrockwell.com/nikon/compatibility-lens.htm#dslr
I don't know why the OP's lens doesn't mount on the D3100. By all accounts it should.

RWR Loc: La Mesa, CA

Thanks for the link.
Edit: I have that link! Should have known better!
Edit 2: According to the chart, a non-modified non-AI lens will not mount on an N6006.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

[quote=forjava]I have 3 non-AI lenses: a 50mm f/2 H, a 50mm f/1.4 S, and a 135mm f/3.5 Q.
The f/2 does not seat in my D3100 or in my N6006, as it should.
That is the problem.

The f/1.4 and f/3.5 seat in my D3100, and in my N6006, as they should.
So, the f/2 lens almost seats but actually it does not.
The edge of each camera body's metal mount is quite visible from the side with the f/2 but is largely covered with the f/1.4 and the f/3.5.
The barrels of the f/1.4 and f/3.5 lenses get closer to the camera body than does the f/2.

Using a caliper, I measure the inner diameter of the f/2 lens barrel at the metal mount.
This metric is smaller in diameter than the diameters of the other two lenses.

Most of the f/2 lenses on eBay have metal mounts with five screws, like my f/1.4 and f/3.5.
My f/2, like a couple of others on eBay has a mount designed without visible screws.



The following is from Ken Rockwell on your 50 F2


Note: Unlike AI lenses, the aperture rings of these pre-AI lenses extend a bit past the mounting flange. I made a differential measurement from the flange mounting surface, not the overhanging aperture ring.

AI Conversion Successful!

As shown, I bought the 50mm Nikkor-H in its original non-AI form.

I bought an AI conversion kit, which is simply a modern AI aperture ring. It was trivial to unscrew the mount (using specialized screwdrivers), swap the old ring for new, and now my 50mm f/2 Nikkor-H from 1972 is fully compatible with matrix metering, auto exposure and full EXIF data on my D3. How's that for Nikon preserving long-term investment value in its lenses?

I found an old, unused conversion kit; I don't think Nikon sells them any more. Nikon did these conversions for only about $25 each until the 1980s, when everyone who was paying attention should have had their old lenses converted.

The AI version came as AI.

Leitz Loc: Solms

According to the OP, he has a different lens than Rockwell's.

Quixdraw Loc: x

John White at AI Conversions -- Comprehensive info and excellent affordable conversions. A gentleman and excellent to deal with. Also referred to by Rockwell.

CathyAnn Loc: Apache Junction, AZ

I don't understand why the lens won't mount on your camera unless it was modified in some way. (Just my opinion.) I have a non-AI lens that mounts on my D5500 - Nikon 200mm Nikkor-Q Telephoto Lens. I even contacted Nikon USA to check on it before I bought the lens, and was told it would mount, no problem.

carl hervol Loc: jacksonville florida

all nikon lens use the same mount but non ai are not milled out on the back and will not fit . at one time you could had them modifed i think that there are people that is still doinging it.

Pablo8 Loc: Nottingham UK.

I sent my Nikon lenses for conversions, back in the 1980's. The only one they could not convert, was the 85mm f/1.8. I can use it on my digital bodies with an extension ring, but only for close-up work.