Nikon 105mm f/2.5

[RalphLambrecht]

Ijust purchsed a copy of thi iconic lens from the last non-AI run. I hope it won't be a problem to convert it to AI. Does anybody have experience with Fototechnik Hofmann in STUTTGART?

 

[ic-racer]

Conversion rings are gonna be hard to find, but in terms of just filing it down anybody should be able to do that

 

[Chan Tran]

I wonder why you didn't get an AI lens to begin with? Some just grind off the aperture ring to make it works but I doubt if you hire someone then there is no saving except you consider the older lens is better?

 

[Paul Howell]

What camera are you going to be using, it is quite usable in stop down metering.

 

[Dan Fromm]

Which 105/2.5? Older Sonnar type or newer double Gauss type?

 

[ags2mikon]

@Dan Fromm That is the most important question. That is why I bought both.

 

[Melvin J Bramley]

If you have a Nikon FE you can lift the AI tab.

 

[RalphLambrecht]

Conversion rings are gonna be hard to find, but in terms of just filing it down anybody should be able to do that

I'm hoping for a precision=machining job

 

[RalphLambrecht]

I wonder why you didn't get an AI lens to begin with? Some just grind off the aperture ring to make it works but I doubt if you hire someone then there is no saving except you consider the older lens is better?

the older lens is the 'iconic' lens and I couldn't find one for a reasonable price.

 

[skahde]

There are two different optical constructions and the earlier one, attributed to be Sonnar-type, has a smaller rear element. Like this one:

Near MINT Nikon Nikkor-P 105mm f/2.5 Portrait Non-Ai MF Telephoto Lens JAPAN | eBay.de

As part of Nikon’s early Nikkor lineup, it reflects Nikon’s long-standing optical design philosophy and remains valued among film shooters and collectors. The 105mm focal length provides strong subject separation and a compressed look, making it ideal for portraits, outdoor shooting, and...

www.ebay.de

All the later ones are of the same double-gauss construction as far as I have been told. The later one worked very well as a portrait lens when i used it as such.
If I wanted to use a nice non-AI lens on a film-body I would use a body capable of doing so, i.e. my Nikon F3. These days, modifying lenses is much more involved than getting another body for the job.

 

[grant.goodes]

Agreed that it is worth seeking out the Nikkor-P Sonnar version, and especially the last run (serial number range 234140 - 286451) as there was a Nikon factory AI kit for them, so you can find them AI'ed but not filed-down by hand. Later Xenotar non-AIs are easily available with factory AI kits already installed as well, but if you're going Xenotar, you might consider the cosmetic changes Nikon made to be a determining factor (sliver vs black nose, metal vs rubber focus-ring, f/32, etc.)

 

[Ian C]

This is best done with a milling machine. All that’s needed is to remove screws holding the lens mount and remove the aperture preset ring. The ring is secured in a the machine’s vice and the shoulder is milled into the rear skirt of the ring. Of course, the shoulder has to be cut at exactly the correct position relative to the aperture scale to form a true raius line for proper registration with the meter coupling lever.

I’ve had the aperture rings on several Nikon lenses machined to communicate with the meter lever on newer Nikon SLRs.

John White in Ann Arbor Michigan still offers this service in 2026. He converted a couple of lenses for me.

https://sites.google.com/view/aiconversions/home

There are a few Nikon AI kits available via eBay, but none for the 105/2.5 at this time.

Nikon Ai Conversion Kit for sale | eBay

Get the best deals for Nikon Ai Conversion Kit at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!

www.ebay.com

 

[RalphLambrecht]

This is best done with a milling machine. All that’s needed is to remove screws holding the lens mount and remove the aperture preset ring. The ring is secured in a the machine’s vice and the shoulder is milled into the rear skirt of the ring. Of course, the shoulder has to be cut at exactly the correct position relative to the aperture scale to form a true raius line for proper registration with the meter coupling lever.

I’ve had the aperture rings on several Nikon lenses machined to communicate with the meter lever on newer Nikon SLRs.

John White in Ann Arbor Michigan still offers this service in 2026. He converted a couple of lenses for me.

https://sites.google.com/view/aiconversions/home

There are a few Nikon AI kits available via eBay, but none for the 105/2.5 at this time.

Nikon Ai Conversion Kit for sale | eBay

Get the best deals for Nikon Ai Conversion Kit at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!

www.ebay.com

John White did a perfect job on one of my lenses a while back. Given the current tax and import/export situation between Europe and the US, I'm hesitant to send another one there right now. Now, I have one on the way to Hoffmann this time. They estimated $70 over the phone and told me that they still do a lot because of the popularity of old Nikon glass. I'll report as soon as I get the lens back. It is the iconic 105mm f/2.5, soon to be AI. It's in perfect shape optically and cosmetically, and I got it for $225. It's well worth spending another $70 on it for me.

 

[Cholentpot]

Nothing to add other than I have both versions and they're both my favorite portrait lenses. I use the non AI version with my FE, F3, F and F2. Anything newer I pick up some other build.

 

[grant.goodes]

Nothing to add other than I have both versions and they're both my favorite portrait lenses. I use the non AI version with my FE, F3, F and F2. Anything newer I pick up some other build.

Is your non-AI copy the Sonnar or Xenotar version? I only recently acquired a Sonnar copy, and do find it has a subtly different rendering than my AiS copy of the amazing 105/2.5

 

[RalphLambrecht]

Is your non-AI copy the Sonnar or Xenotar version? I only recently acquired a Sonnar copy, and do find it has a subtly different rendering than my AiS copy of the amazing 105/2.5

mine is a Xenotar version,which I don't mind.

 

[Cholentpot]

Is your non-AI copy the Sonnar or Xenotar version? I only recently acquired a Sonnar copy, and do find it has a subtly different rendering than my AiS copy of the amazing 105/2.5

I don't know how I would know. It's silver. The new one is black

 

[skahde]

I don't know how I would know. It's silver. The new one is black

A link to the older Sonnar-derived version has been posted above. It can be identified by its smaller rear element and btw. they all have silver parts on them.

Large rear element = Xenotar

NIKKOR-P Auto 1:2.5 f=105mm 440551

This web site documents my Nikon F collection and is trying to show the evolution of the Nikon F System. The site is not finished (will never be) and I am continously adding subjects.

www.destoutz.ch

Small rear element = Sonnar

NIKKOR-P Auto 1:2.5 f=105mm No.284543

This web site documents my Nikon F collection and is trying to show the evolution of the Nikon F System. The site is not finished (will never be) and I am continously adding subjects.

www.destoutz.ch

 

[grant.goodes]

I don't know how I would know. It's silver. The new one is black

All the Sonnar lenses had a silver-snout, but some Xenotar lenses also had the silver-snout, so that isn't definitive. The best visual indicator is the size of the rear-element: The Sonnar design is notably smaller and inset from the black light-baffle, while the Xenotar's rear element is the full size of the light-baffle.

Of course the lens' serial-number is an absolutely reliable way to tell, with the Xenotar starting in the 4xxxxx range (Sonnar is in the 1xxxxxx or 2xxxxxx range). For all this information, see Roland Vink's website.

 

[Cholentpot]

A link to the older Sonnar-derived version has been posted above. It can be identified by its smaller rear element and btw. they all have silver parts on them.

Large rear element = Xenotar

NIKKOR-P Auto 1:2.5 f=105mm 440551

This web site documents my Nikon F collection and is trying to show the evolution of the Nikon F System. The site is not finished (will never be) and I am continously adding subjects.

www.destoutz.ch

Small rear element = Sonnar

NIKKOR-P Auto 1:2.5 f=105mm No.284543

This web site documents my Nikon F collection and is trying to show the evolution of the Nikon F System. The site is not finished (will never be) and I am continously adding subjects.

www.destoutz.ch

Thanks. Yep. I have a Sonnar.

All the Sonnar lenses had a silver-snout, but some Xenotar lenses also had the silver-snout, so that isn't definitive. The best visual indicator is the size of the rear-element: The Sonnar design is notably smaller and inset from the black light-baffle, while the Xenotar's rear element is the full size of the light-baffle.

Of course the lens' serial-number is an absolutely reliable way to tell, with the Xenotar starting in the 4xxxxx range (Sonnar is in the 1xxxxxx or 2xxxxxx range). For all this information, see Roland Vink's website.

No.169386

Can you explain to me in goofus terms why the Sonnar is more coveted? I'd like to brag about it at the next meetup. Where it'll be me meeting up with me.

 

[RalphLambrecht]

Thanks. Yep. I have a Sonnar.



No.169386

Can you explain to me in goofus terms why the Sonnar is more coveted? I'd like to brag about it at the next meetup. Where it'll be me meeting up with me.

the Sonnar is said to render smoother with a more pleasing bokeh.

 

[grant.goodes]

Thanks. Yep. I have a Sonnar.

Can you explain to me in goofus terms why the Sonnar is more coveted? I'd like to brag about it at the next meetup. Where it'll be me meeting up with me.

Well, "coveted" might be an exaggeration! I would say that Nikkor-collectors like to celebrate the arcane history and lore of the more renowned lenses, into which category the 105/2.5 definitely falls. The fact that Nikon made the transition from the Sonnar to the Xenotar design (in 1971) while keeping the lens's mechanical design largely unchanged (the silver snout) means that if you are just casually looking through a selection of used 105's, you might not even realize that some of them were Sonnars unless you really knew what you were looking for. Clearly, Nikon updated the design to improve the lens's optical performance, so they felt the old Sonnar layout could be bettered, but better isn't always what you want, and some photographers preferred the rendering of the older design, and sought out copies of them and "told their friends". As noted above, the Sonnar is noteworthy for its Bokeh, and pleasing rendering wide-open at portrait distances.

Of total non-AI production, approximately 130K copies were Sonnar design, and 190K were Xenotar, so the Sonnar certainly isn't uncommon (for that you would be talking the early 9-blade aperture version, or the super-rare "tick-mark" copies), but I think for sure any fan of the 105/2.5 should consider owning (and using!) a copy of the Sonnar.

 

[skahde]

the Sonnar is said to render smoother with a more pleasing bokeh.

Which could just mean it is less corrected for spherical abberation. It can be a good thing, obviously.

 

[Cholentpot]

the Sonnar is said to render smoother with a more pleasing bokeh.

I've been using them with 400 B&W film pushed a stop or two so smoothness isn't really in for checking on. I'm getting a camera soon that will allow me to adapt these, I'll test out and see if there's a difference to my eye.

Well, "coveted" might be an exaggeration! I would say that Nikkor-collectors like to celebrate the arcane history and lore of the more renowned lenses, into which category the 105/2.5 definitely falls. The fact that Nikon made the transition from the Sonnar to the Xenotar design (in 1971) while keeping the lens's mechanical design largely unchanged (the silver snout) means that if you are just casually looking through a selection of used 105's, you might not even realize that some of them were Sonnars unless you really knew what you were looking for. Clearly, Nikon updated the design to improve the lens's optical performance, so they felt the old Sonnar layout could be bettered, but better isn't always what you want, and some photographers preferred the rendering of the older design, and sought out copies of them and "told their friends". As noted above, the Sonnar is noteworthy for its Bokeh, and pleasing rendering wide-open at portrait distances.

Of total non-AI production, approximately 130K copies were Sonnar design, and 190K were Xenotar, so the Sonnar certainly isn't uncommon (for that you would be talking the early 9-blade aperture version, or the super-rare "tick-mark" copies), but I think for sure any fan of the 105/2.5 should consider owning (and using!) a copy of the Sonnar.

I've also got a 100mm E lens which ain't too bad itself either.

 

[grant.goodes]

I've also got a 100mm E lens which ain't too bad itself either.

I also have the 100/2.8 Series-E (got it in-box for $100, so couldn't resist). It is _super_ compact, doesn't even seem like a telephoto. It is single-coated, so does flare, but seems to render rather well for such a cheap&cheerful 4/4 optical design. Given how much I love my 105/2.5 AiS, the 100/2.8E probably won't get much use, but I agree it "ain't too bad"!