Optical differences between the 105mm 2.5 generations

[PeterN]

Excuse me if this question has been asked already but I failed to find it.

Are there any optical differences between the various generations of the Nikon 105mm 2.5 lens?

Although I was looking for an AI version of the late seventies, my local Nikon Repair man found a K version (nr 674xxx) in excellent condition in one of his cabinets. Since I use the So I bought that one from him. Although specifications up to AI version are the same according to Ronald's site,  I am curious if there are any optical differences. I've read somewhere that Nikon made some changes over time.

Thank you.

[MEPER]

The early one (Nikkor-P) with narrow focus ring and chrome barrel has clearly another optical design than the later versions. I have both versions. The early one I have has no. 197838 and the rear lens element is much smaller than the later ones. I have never tried the early version so can't say something about the optical quality but I have read that the later versions should be slightly better (what that means I don't know as there are so many lens parameters you can compare so I guess you could find a specific area where the early version is better than the later depending what you focus on. It can be very subjective). I am sure the early Nikkor-P is a very nice portrait lens. 

[Birna Rørslett]

The versions of the 105/2.5 with a large rear element are basically unchanged in their optical design over time. Meaning K, AI, and AIS all have the same optics. There are differences in coating and the newest version, AIS, has got straight-edged aperture blades instead of the slightly curved ones of the K and AI. I do prefer the latter as it has softer bokeh.

I do remember back in the early '70s when I had to replace my older 'P' with the 'PC' 105 (the first one was stolen), and how amazed I was about the increase in image contrast and vivid colours with the 'PC' multi-coated variant. Both were K, though. Some years later I added an early AI which remains my overall 105 favourite to this day.

[richardHaw]

i have a nice comparison in richardhaw.com outlining the visual differences.

optically, the tele-sonnar ones have a higher field curvature at least thats how i saw it.
they all perform similarly with the later gauss ones showing characteristics that look more in-line with modern optics
by modern i mean lenses made from the 1980s...

i personally prefer the older tele-sonnar rendering characteristics but that's just me

[PeterN]

Meer, Birn and Richard: Thank you for your replies. Much appreciated!