pre AI vs AI % AI-S

[buggz]

Hello,

Some question here, regarding the 135mm 2.8 and the 105mm 2.5.

135mm pre-AI has 4 elements in 4 groups, and is multi coated (I am refering to the K mount pre-AI, and not the Auto Q or Auto QC). And the AI/AI-S has 5 elements in 4 groups.

Similarly the 105mm f2.5 P Auto has only a single coating (the Auto PC had multi, then onto the AI era), it has 5 elements in 3 groups, which was upgraded to 5 elements in 4 groups for AI era.

Does anyone know what the practical differences are between pre and post AI, and have some experience owning these? I use them on a mirrorless camera, and have several copies of each, however I cant see a difference really.

 

[unpopular]

pre-artificial intelligence versus artificial intelligence and ARTIFICIALLY INTELLECT SQUIRRELS!!

 

[buggz]

go home squirrel you drunk

 

[Dave442]

I often used the pre-AI 135mm f/2.8 lens on a Nikon F. This was F mount, I believe the K was for a later version with rubber focus ring, I still prefer the older metal focus ring.
The P is Penta for the five elements. C is for the coating.
As long as your mirrorless adapter does not have a feeler for the AI then you can mount either lens on it. If it has a feeler then you cannot mount the pre-AI lens on it. Sounds like a fun way to use these older lenses. Of course many pre-AI lenses were later modified to work on DSLR's.

 

[Derrel]

"Practical" differences on mirrorless are not very significant, since the pre-AI models will mount without hitting anything around the mount, like the Ai coupler or the minimum aperture-sensing pin. If you yourself cannot see any differences, then there really are no practical differences, right?

 

[buggz]

Hey Derrel, yeah you right. I was thinking since I'm not a "Nikon guy" and only relatively new to Nikkor lenses, that if there were common knowledge surrounding the differences in optics and results (Auto Q/Auto QC/Pre-ai K mount/AI/AI-s) , particularly lens flare and what-have-you, I would love to hear examples. By practical I meant optically, as any physical issues such as mount differences and AI couplers are not an issue with mirror-less.

 

[buggz]

Hey Dave, the 105mm has the P and PC, whereas the 135mm has Q Auto and QC Auto as differences in models.

 

[Derrel]

Bjorn Rorslett's Lens Review pages on the web would probably be the best source for difference on the 105 and other earlier lenses...I thought the oldest 105 model was a Sonnar design, with a small rear element, and was not quite as well-optimized for close-in work as the later 105mm lenses...seems like I read that on his page some time ago.

There are three thing you will definitely notice between Ai and Ai-S lenses. First off, AI lenses typically have much stiffer focusing ring travel, whereas the Ai-S lenses were designed with a much lighter touch, lower-force focusing ring travel. Second, Ai lenses tend to focus with a slower focusing rate...more turn of the ring from lock-to-lock. And third, the cosmetics of the lenses look different between many AI and Ai-S models. One last thing is that some of the AI-S lenses had built-in sliding lens hoods, whereas the Ai models did not, such as on the 105mm Ai with a separate, screw-in lens hood, and the 105 Ai-S, with its built-in sliding shade. Last, a number of the Ai-S lenses had CRC or close-range correction floating element designs, designed to give better flatness of field at closer-range shooting distances. The 105 Ai-S was a CRC model with sliding shade and a simply magnificent, silky-smooth focusing action.

 

[buggz]

Thanks Derrel

 

[Dave442]

The Q is for Quadra (four) elements.

 

[buggz]

The Q is for Quadra (four) elements.

Oh cool. Seems obvious now, but thankyou! Do you know of any optical differences between the P's and Q's and the AI-S's?
Derrel has mentioned some body and aesthetic differences. This si the sort of information I'm after.

Cheers Dave

 

[Dave442]

I expect that any of the Nikon f/2.5 or f/2.8 lenses in 105mm or 135mm range will give excellent results. I also had some 135mm f/3.5 lenses and the faster lenses were usually better. With or without coating should not be too much of a problem if you watch for flair. You should also be able to use AI or AI-S with equally good results. The AI-S added a slot to help the camera know the aperture setting.

 

[Tim Tucker]

Hello,

Some question here, regarding the 135mm 2.8 and the 105mm 2.5.

135mm pre-AI has 4 elements in 4 groups, and is multi coated (I am refering to the K mount pre-AI, and not the Auto Q or Auto QC). And the AI/AI-S has 5 elements in 4 groups.

Similarly the 105mm f2.5 P Auto has only a single coating (the Auto PC had multi, then onto the AI era), it has 5 elements in 3 groups, which was upgraded to 5 elements in 4 groups for AI era.

Does anyone know what the practical differences are between pre and post AI, and have some experience owning these? I use them on a mirrorless camera, and have several copies of each, however I cant see a difference really.

Ai is not a designation for optical design. It stands for Aperture Indexing and signifies the shift of the coupling that tells the camera what aperture is set from the pentaprism to the lens mount, Ai lenses are all backward compatible and so still have the 'rabbit ears'.

Similarly the K designation just marks a shift in appearance and was a move to rubber focus rings across the whole range of lenses, these are all pre Ai lenses.

The P's and Q's just indicated the number of lens elements and not necessarily lens design. The C designation (as in QC or PC) indicated a multicoated lens and were introduced just before the K designation.

The 105/2.5 has two basic optical designs, the earlier Sonnar and the later Gauss. All PC, K and Ai lenses are Gauss design (also some P Auto). Basically if it has a silver filter ring then it's a Sonnar, black and it's a Gauss. Designed as a portrait lens both are very sharp and were deliberately under-corrected with certain aberrations to produce smooth out of focus areas, (bokeh). The Gauss is the better optical design and has improved close focus but some still prefer the slightly smoother rendering of the Sonnar.
I have both and they are both superb lenses. Here is a grab shot with my 1966 Sonar quite literally just after I'd reassembled it after servicing and Ai converting. Shot at 3200ISO and f2.8. Don't be fooled by the age of these lenses. (N.B. It was the Micro-Nikkor 105/2.8 Ai-S that had the CRC not the Gauss design 105/2.5 which remained unchanged from it's introduction in 1971 right up to 2005. Again the Ai-S designation was to do with Aperture indexing and is no indication of optical design).

With the 135/2.8 the design was changed during the K designation so the earlier K lenses were of the same optical design as the QC, later K lenses were of the slimmer design. These later designs were probably to do with reducing the size and improving the ease of manufacture so don't go looking too hard to find the differences.