AI Conversions and "Forking" Lenses

[ben_hutcherson]

I've recently gotten in to buying/collecting some earlier Nikon pieces. Even though I was am still am a Canon nut, the F-series bodies fascinate me and I've enjoyed learning about and using some of the great old glass.

 

With that said, I've of course run into plenty of non-AI lenses. For most of them(including a couple of different 50mms) I also have a companion AI lens, so that's not a problem. I also generally try to buy earlier AI lenses with the fork so that I can use them both on AI and non-AI bodies.

 

I have a couple of lenses, though, where I don't have an AI counterpart. One of the problems I've run into is with "standard" 50mm lenses. I have a bunch of them. The Micros are no problem, as I have both a non-AI along with an early "forked" AI lens. I have two 50mm 1.8s-one a Series E, and the other the first generation AF version. Neither of these have forks, although if I were so inclined I think that could be fixed on the AF lens. My only 1.4 is non-AI, although I'd honestly rather just get an AI version since that's not a super expensive lens in any trim.

 

All of my bodies I currently own allow me to use non-AI lenses, and I've actually been reading up on and considering a Df since it ca be used with non-AIs.

 

All of that aside, though, I have a very nice 20mm f/3.5 non-AI. It's the early one with the "big" front element. I'd actually really like to do a proper AI conversion on it-I've run across folks who will mill the aperture ring, but of course I also don't want to lose the fork and also am not wild about the labels that are used. If I did convert it, I'd like to do it right with the replacement aperture ring, but I can't seem to find one. Does anyone know if these are available anywhere?

 

Second, I'm also attracted to the fact that there are a lot of new lenses out there that I can still use on my F and F2. The ones I've looked at still have the pilot holes on the aperture ring for the coupling fork. Is this a service that Nikon still offers, or do I need to find a 3rd party to do it? Obviously, I'd prefer Nikon do it since I'd hate to blow $1K on a new lens and then void the warranty by having 3rd party work on it. I realize this is an obscure question(I'm guessing folks buying new lenses for an F2 or the like probably use an F2A or F2AS that doesn't require the fork) and that aperture rings are basically an endangered species on new lenses. Even so, the less compatibility(even though it's full of astericks and exceptions) is a big attraction to me with the F mount.

[Gary Naka]

AI conversion kits are ify. Some are available, other seem to be non-existant. I am looking for 2 of these non-existant kits, and doubt I will find them. It has been too long since Nikon made those kits, and the pipeline is dry.

 

Contact Nikon about having their service dept install the coupling prong.

 

Be careful on the digital bodies.

Some may allow you to mount the pre AI lens, but won't meter with them. I'm not familiar with the Df.

[Dieter Schaefer]

Check out John White at AI Conversions for Nikon Lenses: Effective, Fast and Affordable!

[Sandy Vongries]

Second Dieter's suggestion! Excellent guy to do business with.

[robert_bowring]

If the newer lenses that you are looking at have the holes for the coupling fork all you need to do is buy the fork and install it yourself. I have done this for several lenses and they work fine on my F and F2. I have found the coupling forks on ebay for about $10.00.

[Matthew Currie]

I've milled a few lenses, and although the milling does cut into the fork it is still possible to retain it.

 

I think all the manual lenses, AI and AIS, had forks unless they were removed. If the tapped holes are there, it's easy enough to replace the fork. I note on several AF lenses, that there are tiny little holes to provide the correct positioning to drill for the fork, but of course you'll need either to tap the holes or use self tapping screws. The E series lenses are less forgiving, with no pre-configured fork mount. The 75-150 zoom, for example, not only has no pre-placed holes, but no aperture ring surface prepared, and you'd have to grind it as well as finding the right position for the fork. But the dirt-cheap 35-70 Cosina made zoom that came on my FM-10 has the starting holes.

 

Remember too that although a lens without meter connection is less convenient on an F, it is not unusable. It will still work, and you can still do stop-down metering.

 

I would guess, though, that if you're not adventurous and want someone else to do it, John White is probably a good bet.

[ben_hutcherson]

Thanks guys. I am a watchmaker so am not afraid of delicate work, but at the same time I don't know these well enough to feel good about tackling them. I'll check with John White.

 

As I mentioned, the 20mm is my main interest now.

 

Matthew, I think you're right with the exception of the Series E. My 50mm doesn't even have the positioning holes, although it now has a hole where I attempted to mount a form from a Vivitar lens.

 

My F doesn't even do TTL metering-with an uncoupled lens you slide the pin back and forth and then when you've centered the needle you read the correct aperture out of a window in the back of the finder. As another interesting point, this particular finder(the original Photomic finder) also doesn't require you to twiddle the ring to "teach" it the maximum aperture-it just reads it correctly. I've been told it can get away with it because it's not a TTL meter.

 

As for the Df, I've read good and not-so-good things about the body, but AFAIK it's the only digital body made with a "flip up" AI fork so it can both safely mount non-AI lenses and meter correctly with non-chipped AI lenses.

[Sandy Vongries]

Ben -- most of us who have one (at least that I've talked with) love the DF. I've had mine since the Summer of '14. I much prefer it over my D 750. I was hoping for a DF 2, Now I may well get rid of the 750 and buy another DF. It has never let me down, and is the camera I usually reach for. I have a substantial number of old Nikkor lenses, both AI and before, which work beautifully on the DF. That was the primary reason I chose it, and have never regretted the purchase.

[ben_hutcherson]

Ben -- most of us who have one (at least that I've talked with) love the DF. I've had mine since the Summer of '14. I much prefer it over my D 750. I was hoping for a DF 2, Now I may well get rid of the 750 and buy another DF. It has never let me down, and is the camera I usually reach for. I have a substantial number of old Nikkor lenses, both AI and before, which work beautifully on the DF. That was the primary reason I chose it, and have never regretted the purchase.

 

Thanks for the endorsement of the camera.

 

As I said, in all honesty I AM a Canon guy. I still love shooting film, but there are times when digital is necessary/proper/just the best choice. My Rebel is a tool, and while it serves my needs well enough it does come up lacking in several areas. To be fair, I only used the kit lens on it for a while. I bought the fantastic 100mm 2.8 Macro(non-IS) about a year ago and that lens made me realize that man of the deficiencies I thought I was seeing were in the lens more so than the camera.

 

Even so, I'd still like to expand my digital kit, and the Df seems like the perfect camera for someone like me who wants to pack film cameras-and especially good manual cameras-along side a digital body. I also like knobs and switches-part of the reason why I really like the F4. I realize it's probably not a camera for everyone, but I'm glad to know that folks who are attracted to it for the same reason as I am find that it suits them.

 

The "backwardness" of Nikons is still throwing me off, but at the same time I've been making myself use them. Preparations are in full swing to dress our state Capitol up for the Derby, and I spent about an hour walking around the grounds this afternoon with my F3 around my neck and swapping between a 28mm 2.8 and 55mm Micro as appropriate. I burned through a roll and a half of Velvia, and I have to admit that I'm warming up to it even if I'm constantly turning the shutter speed dial or aperture ring the wrong direction. I still have to get use to the fact that Nikon lets the shutter speed dial turn completely around(I've used F-1s and related bodies a lot, and one of the things that I've always taken for granted is that I can set shutter speeds without looking at anything based on the hard stops at both extremes of the dial).

[Gary Naka]

Oh dang, the F3 does not have hard stops on the shutter speed dial????

Maybe I need to go look for another F2.

[ben_hutcherson]

The F3 sort of does, as it will "lock" into the A or X positions if you turn it there. That just annoys me even more, though, since you have to push the button in the center to unlock the dial.

 

The F and F2 don't have stops either, although the metered finders DO have stops.

[Gary Naka]

Ah that is why I did not notice, I have the photomic prism on my F2.

[NetR]

Please note that all Nikon Series E lenses are AIS.

 

The fork was initially required to signal to the Photomic head what the maximum aperture was - the first Pentax 6x7 had a similar arrangement. The fork was no longer needed for bodies made after around 197,7 but continued to be added to lenses to ensure compatibility between the old camera bodies and the newer AI, then AIS, lenses. I understand it is possibly to add a fork to an AF lens.

 

This article by THom Hogan shows which lenses are compatible with which camera bodies. Nikkor Lens Information by Thom Hogan

[robert_bouknight1]

I have had several lenses "AId" by John White, all work well and retained an operational fork, although some of the fork base was milled away in the process.

 

Also, some of the earlier lenses that lack the fork, but have a aperture ring have dimples where screw holes would be located for a fork.

 

Interestingly, Johw W. wrote me a note before doing my 5.8CM/1.4 asking me if I was sure since the lens was somewhat collectible. I had sent him a pretty well worn 5.8CM on purpose, still have a nice "uncut" 5.8CM in the cabinet to go with my early F. Pretty sure there was never a factory conversion kit for the 5.8CM.

 

I am glad to have a workable 5.8 for the DSLRS, the lens renders very nicely at around f/2 for full length portraiture, so I don't have to buy one of the new 58mm lenses, LOL.

 

Of course, lenses with a factory AI conversion ring are a little nicer than a milled one, but I would not hesitate to modify a lens that fills a photographic need. I would probably just try to find a user grade version of that lens rather than mill a mint original one, though.

[glen_h]

doesn't require you to twiddle the ring to "teach" it the maximum aperture-it just reads it correctly. I've been told it can get away with it because it's not a TTL meter.

 

A TTL meter needs to know how far you set the aperture ring down from full aperture. That is, how much less light there will be.

 

A non-TTL meter needs to know the actual aperture setting, and doesn't care where maximum is. As well as I know, the fork was added for the original non-TTL photomic finder.

 

The AI ring only tells how far it is down from maximum. For some DSLRs, you can tell the camera the maximum aperture, and it will generate the appropriate EXIF data.