85mm f2 AI good enough or must it be AIS?

<p>I am building up a Nikon film kit with used gear. So far I have a mint 20mm f2.8 AIS, a far from mint FM2n (but works well) and I am looking for an 85mm f2. Question is, should I wait for an AIS (begun in 1977) or buy a reasonably priced AI (1971). My understanding is there is no real difference though the coating changed from green to pinkish. <br>

Any opinions? Thanks.</p>

<p>Your dates are off. AI began in 1977; AI-S in 1981.</p>

<p>In most cases, there is no optical difference between AI and AI-S lenses. The 28mm f/2.8 is one of the exceptions; it was completely reformulated for the AI-S version, which is much better than the older AI model. But the 85mm f/2, as far as I know, has the same optical design in AI and AI-S, though as you say there is probably a difference in coatings.</p>

<p>In most cases the AI-S lenses have shorter focus throws, which means AI can be preferable for more precise focusing. Other than that, the difference between AI and AI-S is only meaningful for a very few Nikon camera models: the FA, the FG, and I think the F4 and perhaps one other non-pro model of the 1980s. Other Nikons can't tell the difference between AI and AI-S.</p>

<p>Thanks Craig, I checked, you are right. The lens was billed as 1971 but that was wrong. I'm going to go for it. I like the compactness and at that focal length I should get good blur at f2. </p>

<p>Optically they are identical, and I suspect there is little difference in the multicoatings between the Ai model and early production of the AiS. There are some significant mechanical differences in internal construction, but the only real functional difference is the focus throw as Craig indicated above (255° vs. 170°). The linear actuation of the aperture stopdown (AiS) is of no real importance unless you are considering retrofitting a CPU chip for use on cameras that can't meter with non-CPU lenses.</p>

<p>Only the FA and N2000/N2020 (F-301/F-501) take full advantage of the features of AiS (high speed program shift). The FG uses the lens speed post for P mode, but doesn't have an AiS detection pin. The F4 uses the lens speed post (Ai and AiS) for matrix metering, and it has an AiS detection pin, but it doesn't really appear to do anything with it since the camera is crippled and can't use P or S modes with manual focus lenses. And all of the above are perfectly happy with Ai lenses in any AiS compatible exposure mode.</p>

<p>Either one will be a handsome addition to your FM2n, although the earlier Ai model will probably have a worthwhile advantage when it comes to purchase cost. Enjoy. :)</p>