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Archive 2016 · Why Doesn't Pre-AI Mount?

  
 
Lee Saxon
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p.1 #1 · p.1 #1 · Why Doesn't Pre-AI Mount?


Something I never learned somehow. What is it about pre-AI lenses that prevent them from mounting? Slash how do you recognize a lens which has been modified?

I'm interested in the answer in general but in particular I'm curious about my 1000/11 Reflex-C. It's technically pre-AI. But I don't know if the lack of a diaphragm makes that irrelevant or if mine, which mounts just fine on every DSLR I've tried, has been modified.



Dec 24, 2016 at 11:37 PM
BSPhotog
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p.1 #2 · p.1 #2 · Why Doesn't Pre-AI Mount?


Here's a good write-up with some images.

http://www.kehblog.com/2011/10/nikon-lenses-non-ai-ai-ai-s-and-aid.html



Dec 25, 2016 at 12:02 AM
Joseph.
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p.1 #3 · p.1 #3 · Why Doesn't Pre-AI Mount?


I'll keep this short... LEFT is a Pre-AI lens. RIGHT is an AI lens. See how the aperture ring on the left is perfectly flat and missing the ridge that's present on the right?



Now if you look at your Nikon body, you'll see that it has an aperture prong/lever:



If you mount a Pre-AI (or non-AI) lens, it will crash with this lever and damage it. Simple.

The only exception is the Nikon Df, where you can FLIP this lever UP so you can mount a Pre-AI lens, and flip DOWN to use normal lenses:





Dec 25, 2016 at 03:03 AM
the solitaire
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p.1 #4 · p.1 #4 · Why Doesn't Pre-AI Mount?


135mm f2,8 Nikkor-Q on the left, 135mm f3,5 Nikkor-Q on the right.

Very nice lenses, both. I own both. Have the Nikon Ai kit for the f2,8 lens and cut the aperture ring on the f3,5 so both mount on my D3 and girlfriends D800.

I guess I do need a Nikon Df though because I now own some lenses for which I can not find an Ai ring and that are so clean and old that I do not wish to cut them.

Lenses that fit without cutting the Ai ring, but after removing the coupling prongs are:

20mm f3,5 Nikkor-UD
2,8cm f3,5 Nikkor-H
35mm f2,8 Nikkor-S
5cm f2 Nikkor-S

Other cameras that feature the articulating indexing lever are:

Nikon FM (not FM2/FM3)
Nikon F3, F4
Some APS modified Nikon F5's

Cameras that don't care:
Plain prism or WLF Nikon F and F2
Entry level motorless DSLR's

Since none of those meter, but all of them have the spring mechanism operating the automatic aperture, the lenses can be used wide open or stopped down and all you need to play is sunny 16 or a lightmeter app.

Some medium budget dSLR's have a wide open aperture indexing thingy that get's in the way even if the lens' aperture ring was cut. D90 is an example of those. Not sure which other cameras feature that lever.

In particular on that 1000mm f11, since it has no aperture, the skirt on the lens mount has been kept high so it doesn't interact or interfere with the above mentioned levers



Dec 25, 2016 at 07:27 AM
Lee Saxon
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p.1 #5 · p.1 #5 · Why Doesn't Pre-AI Mount?


Thanks y'all!


Dec 25, 2016 at 02:38 PM
saph
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p.1 #6 · p.1 #6 · Why Doesn't Pre-AI Mount?


One pre-AI lens that needs no modification is the Nippon Kogaku 10.5cm f4 T. Must be similar to what Buddy's describing on the 1000mm reflex lens. The 10.5 T has a preset aperture ring in the front, so the "skirt" in the rear doesn't exist.

Actually yet another vintage pre-AI lens that needs no modification is the 5.5cm f3.5 Micro-Nikkor, again with a preset aperture in the front. You wouldn't want to be modifying its rear anyway.



Dec 25, 2016 at 02:49 PM
mawz
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p.1 #7 · p.1 #7 · Why Doesn't Pre-AI Mount?


It's worth noting that most modern Nikon's without an AI tab have a lever switch around the 8 o'clock position on the mount that will get damaged if most pre-AI lenses are mounted. This switch detects that the aperture ring on AI lenses is set to the smallest aperture.

Some few digital bodies (the D40/X/60 and D3x00's) use a cheaper pushbutton switch in this location and are the only Nikon digital bodies aside from the Df where you can safely mount any pre-AI lens that doesn't require mirror lockup.



Dec 26, 2016 at 01:50 PM
Artscar2
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p.1 #8 · p.1 #8 · Why Doesn't Pre-AI Mount?


Add the wonderful Nikon FE to the switch-hitting team of moveable indexing levers. And great answers here by the way.


Dec 27, 2016 at 12:10 AM
mawz
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p.1 #9 · p.1 #9 · Why Doesn't Pre-AI Mount?


Artscar2 wrote:
Add the wonderful Nikon FE to the switch-hitting team of moveable indexing levers. And great answers here by the way.


True, but hardly a modern design. The FE, FM, Nikkormat FT3 and EL2 and the F2A/AS & F3 all were AI bodies with pre-AI support. Aside from the single-digit F's, pre-AI support was completely gone in the line by 83 (when the FE/FM were replaced by the FE2/FM2n)



Dec 27, 2016 at 12:13 AM
AmbientMike
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p.1 #10 · p.1 #10 · Why Doesn't Pre-AI Mount?


Someone was saying that the F4 had a flip up AI coupling, and that it would take pre-AI lenses. Are you interested in film or digital bodies? I don't think it's any trouble adapting to m4/3 or Canon. Not completely sure, though


Dec 27, 2016 at 12:14 PM
mawz
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p.1 #11 · p.1 #11 · Why Doesn't Pre-AI Mount?


AmbientMike wrote:
Someone was saying that the F4 had a flip up AI coupling, and that it would take pre-AI lenses. Are you interested in film or digital bodies? I don't think it's any trouble adapting to m4/3 or Canon. Not completely sure, though


Yes, the F4 had the flip coupling, the F5 didn't, but Nikon would install one for you as an option, the F6 didn't officially have the option, but was compatible with the F5 unit. Nikon no longer stocks/makes the coupling for the F5.



Dec 27, 2016 at 06:33 PM
gyoung143
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p.1 #12 · p.1 #12 · Why Doesn't Pre-AI Mount?


I thought my FM2n had the flip up lever?
I am away from home so can't check it!

Gerry



Dec 28, 2016 at 08:48 AM
mawz
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p.1 #13 · p.1 #13 · Why Doesn't Pre-AI Mount?


gyoung143 wrote:
I thought my FM2n had the flip up lever?
I am away from home so can't check it!

Gerry


You'll find it doesn't, unless there's an aftermarket mod. FM had it, FM2 didn't, FM2n inherited the lack from the FM2.



Dec 28, 2016 at 03:01 PM
Ray S.
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p.1 #14 · p.1 #14 · Why Doesn't Pre-AI Mount?


the solitaire wrote:
I guess I do need a Nikon Df though because I now own some lenses for which I can not find an Ai ring and that are so clean and old that I do not wish to cut them.


I have a DF and a few lenses like that, but I eventually cut them anyway. The minor hassle of having to set the aperture twice (once on the lens, once on the camera) was one thing. But the bigger thing was remembering which lenses had been cut and which hadn't when changing them out, and remembering to flip the little tab on the body between ai and non-ai position. After putting non ai lenses on a few times without flipping the tab out of the way (luckily without damaging the tab!), I just went ahead and modified the lenses. After all, I didn't buy them to stick in a museum, but to use. And they're much more usable modified... At least for me - not suggesting this is the right solution for everyone...

So now all of my non-ai lenses are ai compatible...

-Ray



Dec 29, 2016 at 06:33 AM
the solitaire
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p.1 #15 · p.1 #15 · Why Doesn't Pre-AI Mount?


Ray, in most instances I completely agree.

For me personally the moment where I stop cutting an aperture ring is if the lens is in mint condition and the total production number of lenses is at or below 15000 units. In that case I try to find a more beaten up copy of the lens to replace it. No shelf queens for me either.



Dec 29, 2016 at 10:15 AM
Ray S.
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p.1 #16 · p.1 #16 · Why Doesn't Pre-AI Mount?


the solitaire wrote:
Ray, in most instances I completely agree.

For me personally the moment where I stop cutting an aperture ring is if the lens is in mint condition and the total production number of lenses is at or below 15000 units. In that case I try to find a more beaten up copy of the lens to replace it. No shelf queens for me either.


I hear you. The last one I converted was a nearly mint copy of a 1960 5.8cm f1.4, only about one year younger than me. The only thing that wasn't pretty much perfect on this lens was a previous owner had etched their name onto the aluminum base plate surrounding the rear element. It's otherwise perfect AFAICT, but I liked shooting with it so much I finally said screw it and modified it to use as an AI...But I have to confess that one was pretty tough to disturb and if it hadn't already had the other name etched into the bottom, maybe I would have left it in original condition...

-Ray



Dec 29, 2016 at 11:41 AM
the solitaire
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p.1 #17 · p.1 #17 · Why Doesn't Pre-AI Mount?


Ray S. wrote:
I hear you. The last one I converted was a nearly mint copy of a 1960 5.8cm f1.4, only about one year younger than me. The only thing that wasn't pretty much perfect on this lens was a previous owner had etched their name onto the aluminum base plate surrounding the rear element. It's otherwise perfect AFAICT, but I liked shooting with it so much I finally said screw it and modified it to use as an AI...But I have to confess that one was pretty tough to disturb and if it hadn't already had the other name etched
...Show more

That 5,8cm is most certainly an interesting lens. Always liked the results people got with it, having to work around soft edges and vignetting wide open. The lens also has quite the unique transition from in-focus to out-of focus.



Dec 29, 2016 at 01:40 PM
garysblim
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p.1 #18 · p.1 #18 · Why Doesn't Pre-AI Mount?


I've adapted both pre-AI and AI lenses on my Canon full frame bodies with full metering support. If the adapter comes with AF chip, the body will also give AF confirmation.


Jan 02, 2017 at 09:29 PM
ohsnaphappy
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p.1 #19 · p.1 #19 · Why Doesn't Pre-AI Mount?


I think EVERY SINGLE new Nikon body should have the metal prong, like the Df. What a selling feature that would be!!! All Nikkor lenses would be fully functional. Epic


Jan 05, 2017 at 06:15 PM





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