Medical Nikkor 120mm f4

[David H. Hartman]

Just a quick link to a manual...

https://cdn-10.nikon-cdn.com/pdf/manuals/archive/Medical-Nikkor%20120mm%20f-4%20IF.pdf

Dave

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I think this is the search I used and while look through the hits I found a bunch of Nikkor lenses manuals...

https://duckduckgo.com/?q=Nikon+F+lens+and+camera+bayonet+nomenclature+&t=hx&va=g&ia=web

Many from Nkion Canada

[Macro_Cosmos]

Sorry for digging this thread up.
May someone share the repair manual with me?  Or explain how the aperture and focus linkage can be removed?  I was finally able to purchase one of these and to my surprise, I cannot find any information online regarding the modification.  It sounds simple but from what I have read so far, it might be quite difficult. 

I would like to assume that the optics require no work.

[Birna Rørslett]

Erik should know. Shoot him a PM. Do note you'll need a CPU in the lens to fully exploit the advantages of removing the aperture/flash linkage.

[Macro_Cosmos]

Erik should know. Shoot him a PM. Do note you'll need a CPU in the lens to fully exploit the advantages of removing the aperture/flash linkage.

Thanks a lot Birna!  I will DM Erik later. 
I plan on only using the lens wide open where it should perform the best.  I might add the chip too as I think I have enough skills now to do such a modification.
The other plan is to install an LED ring light powered by a USB power bank to act as some sort of manual focus assist when it gets dark.  I am personally not a fan of the flat ring light look.

 

[Birna Rørslett]

Once you can set the aperture at will, there is no need to use the built-in ring flash at all.

Looking quickly through my archive for images taken with the 120 Medical, I noticed at lot of them were acquired at aperture settings f/11-f/22. Chasing butterflies however were with f/4-f/5.6. So it all dependens on the purpose and motif of the picture.

[Macro_Cosmos]

Once you can set the aperture at will, there is no need to use the built-in ring flash at all.

Looking quickly through my archive for images taken with the 120 Medical, I noticed at lot of them were acquired at aperture settings f/11-f/22. Chasing butterflies however were with f/4-f/5.6. So it all dependens on the purpose and motif of the picture.

Chances are, mine will be used for relatively still subjects such as flowers and slow critters, I will likely do bursts and focus stack.  I have sent Erik a message, thanks!

There were several opportunities to pick this lens up at less than $50, ones that were infested with mushrooms.  I regret it now, I should have bought one to do a trial on before taking the surgery on my nice boxed copy.

[Erik Lund]

I would not say it is quick fix to remove and change/fix the linkage. You need to disassemble the rear quite far to get to it and the set it at smallest aperture to let the camera control it via the stop down leaver, as Birna mention this will only work if an appropriate CPU is installed. If not, the aperture will not stop down correctly,,,
Yes, you can disable the aperture and aperture lever,,, all manual,,, not recommended.

[Macro_Cosmos]

The lens arrived.  It was in such good condition, I would rather leave it without modifications.  I will try and get another unit that I do not mind messing with.

At first glance, the aperture is limited corresponding to each magnification.  However, at higher settings, it can be opened up.  It cannot be closed beyond the fixed settings at low magnifications.  This makes a lot more sense to me now, I was confused about the necessity of contacts to control the aperture, as I thought it allowed no adjustments and had no prong to engage the iris.

All I have to do is to find a ring which engages the aperture, maybe an AI/AIS-M42 ring and then adapt it back to F-mount, get some extension tubes to achieve the correct magnifications.  I only plan on using the lens at higher magnifications anyway, so the handicap does not affect me.

There was even a printed warranty certificate. 
The warranty is only valid in Japan, oh no!  My warranty.   

[Macro_Cosmos]

Looks like the BR-4 ring does exactly what I want it to do, bye spring.
The crude adaptation is now complete.  The aperture prong of the lens itself is spring loaded too, I can just use a piece of tape to stop it from closing.   

[Birna Rørslett]

As long as the lens delivers the images you want, why not?

However, adding extension to that lens to set it to a given magnification might not be the optimum approach for quality. I'm curious about the results.