Nikon 105/2.5 AI-s vs AI: changes between them?

[Jedi]

In case it is not clear from previous responses, the AI and AI-S have the same optical design, so they will render identically.
However the AI has curved aperture blades so the opening is rounder (but not fully rounded), giving background blurs a more organic appearance. The AI-S has straight edge aperture blades so blurs are distinctly polygonal (7-sided).

Both are fully multicoated, using Nikon Integrated Coating (NIC) which is a very good coating. Late production AI-S 105/2.5 lenses with serial no greater than 1043xxx have the newer yellow-green Super Integrated Coating (SIC), but I don't think it makes much difference in practice. If flare or contrast is a problem, shading the front element will make a bigger difference.

My preference is for the AI version due to the rounder aperture and also the longer focus throw. The built-in hood of the AI-S can be of use at times but it is on the short side and tends to be a little wobbly.

Yes, I had understood this.

[Jedi]

Thank you all!!

[richardHaw]

https://richardhaw.com/2017/05/05/repair-auto-nikkor-p-c-105mm-f2-5/

just updated one of my most popular articles 

[JohnBrew]

get the Sonnar version 

sorry, just my preference...i am a Sonnar lover

the Ai is better-built but no hood

I have a hood on mine. HS-4, which specifically states it is for the 105 2.5, 135 3.5 & 105 4.

[Birna Rørslett]

For my 105/2.5 lenses, I us HN-8, which is a screw-in not snap-on type. The latter always is prone to falling off at the most inconvenient of times.

[richardHaw]

i am sure that i have one of those hoods here somewhere...my house is too messy

[MFloyd]

I have a Nikkor-P 105mm f/2.5 (pre Ai, but retrofitted and chipped). It's a Gauss type one i.e minimal focus distance = 1m, and 7 rounded diaphragm blades. Works perfectly with the D850. Careful: aperture should be dialled in on the lens (non linearity of the aperture dial), otherwise you start to be over-exposed on smaller openings. 



I bought it new in 1973....