Adaptation Question - Early Nikkor-S 5cm f2

[Univer]

Hi All,

I'm turning to the collective wisdom of the forum with a Nikon adapter question.

I recently picked up a very nice example of the Nikkor-S 5cm f2 lens - 9 aperture blades, but no tick marks. My plan was to use the lens, with the appropriate adapter, on my E-mount, Canon and Micro-4/3 digital bodies.

I was aware of this lens's deep rear aperture-ring flange, but I hoped that I might still be able to use it, unmodified, with my adapters. Unfortunately, that doesn't seem to be possible. The lens won't lock on to any of my adapters; and I'm confident that even if I were somehow able to get the lens mounted, the aperture ring would be immovable.

I've had success modifying a Nikon-to-Micro-4/3 adapter for use with a NAI 105mm lens, grinding a bit of metal away from the sides of the chrome adapter flange to allow the aperture ring to turn. But the 105mm flange is much shallower than that of the 5cm; that gently modified Micro-4/3 adapter won't work with this lens.

I gather that there never was an AI conversion kit for this early 5cm, so that doesn't appear to be a solution.

My question: is the only realistic option to cut away the lens's protruding rear flange? Has anyone had success - assuming that someone else has adapted this lens - modifying the adapter and leaving the lens untouched? (I would be happy to buy and modify an additional Nikon-to-E-mount adapter for this specific purpose.) I don't want to take the Dremel to this lovely old lens, unless I'm 100% certain that there's no other choice. But having said that, I'm certainly eager to use it; I bought it as a shooter, not as a collector's item.

Thanks for your help!

Cheers,

Jon

[calvin83]

I think this Voigtlander Adapter for Sony E Mount Cameras--Nikon F Mount Lens (Black) might work but it is too expensive. Another solution is to take the mount from an old extension tube, modify and put it into the NEX adapter.

[Univer]

Hi Calvin,

Thanks so much for the suggestion. (And for what it's worth, I agree that the Voigtlander adapter is much, much too pricey.)

You've got me wondering whether it might be possible to put together a homemade adapter without modifying an existing one. For example:

- take a K3 Nikon extension tube (from the original "K" tube set) - that tube is female F-mount on the lens side and 52mm thread on the camera side
- add some additional 52mm thread tubes to approximate the correct register distance
- add a 52mm female-to-M42 male adapter (readily available - I have a few)
- finally add a short M42-to-E-mount helicoid adapter

My understanding is that the original "K" extension tubes work with all non-AI lenses. So I think this arrangement might actually work, although it would be fiddly to get the register distance right. Still, it might be preferable to modifying a lovely old lens.

Does that sound like a possible workaround?

Cheers,

Jon

[calvin83]

I think this will work. If you have helicoid, there is no need to add 52mm tubes.

[Univer]

Hi Calvin,

Excellent idea - the M42 helicoid should make the process much simpler. Thanks so much for your marvelous suggestion! I hadn't even considered using extension tubes as a workaround.

I've ordered a "K" extension tube set; I'll report back on the results.

Cheers,

Jon

[Univer]

Hello Again,

As promised: an update on this adaptation question.

I'm happy to report that the "K" extension-tube solution works very well. I was able to mount the lens on the K3 tube (female NAI mount on the lens side, 52mm screw thread on the camera side), add a 52mm-to-M42 tube and a short M42-to-M42 helicoid, and then mount the entire contraption on my E-mount body via a "short" E-mount-to-M42 adapter designed expressly for helicoid use.

It will be a simple matter to dial in the correct register distance for infinity focus by adjusting the M42 helicoid. (I say "will be" because I was working in the evening, without adequate light to check infinity focus.) Once the helicoid is at the proper length, the lens's own focus ring will be able to take over, and the engraved scales will be accurate.

This is a really welcome alternative for adapting problematic NAI lenses to any of the short-register digital platforms…without resorting to lens modification. Not much help for Canon shooters, sorry - the only option there might be to use the K1 extension tube (NAI mount at both ends) and accept the loss of infinity focus.

Calvin, thanks again for your extraordinarily helpful suggestion! It's much appreciated.

(Now if only I can get the aperture mechanism to behave itself…)

Cheers,

Jon

[calvin83]

This is a good news. I think most people will decide modify the lens instead of buying expensive adapter or DIY adapter.

Look forward for the samples.

[Univer]

Hi Calvin,

Sadly, I think you're right - most people would probably opt to modify the lens.

I've modified a lens here and there over the years in order to adapt it successfully, but those were "user" lenses. I've also ground away a few Fujica M42 aperture tabs, but I don't count that as a significant modification.

In this case, the lens was simply too nice to modify irreversibly. And I gather the 9-blade Nikkor-S is a minor collector's item - not in the same league as the tick-mark version, of course, but still desirable.

Samples will be forthcoming, as soon as I coax the aperture mechanism back into reliability.

Thanks again!

Jon