Both versions share the same optical formula of 5 elements in 5 groups, with the Ai-S version featuring improved coatings with a distinctive pinkish cast on the front element, as opposed to the greenish coating of its predecessor. As part of its historical development, the lens was created to replace the discontinued Nikkor 85mm f/1.8 (K).
The lens follows Nikon's traditional approach of all-metal and glass construction typical of that era, a solid metal body with a wide, checkered focusing ring that operates smoothly and allows for end-to-end focusing without needing to readjust your grip. The aperture ring is particularly noteworthy, often described as "probably the smoothest" among vintage Nikon manual focus lenses, with positive clicks and buttery smooth operation all the way on the aperture ring.
Physical attributes of the lens include a compact form factor, which is 61mm in length and 60mm in diameter, a weight of around 310 grams, which makes the 85mm a remarkably compact lens, roughly the size of most other 50mm lenses of the era, and significantly smaller than competing 85mm options. The lens accepts 52mm filters and normally comes with an optional HS-10 lens hood.
The focusing mechanism of the Nikkor Ai-S 85mm f/2 features a 170-degree focus throw on the Ai-S version, which is shorter than the 255-degree throw of the original AI version, making it faster to focus while maintaining precision. The lens focuses down to a minimum distance of 0.85 meters.
On the Olympus E-P5, with a focal length equivalent to a 170mm tele on a full-frame camera, the lens is sharp across the frame when stopped down slightly, accentuated by its almost perfectly flat field at portrait distances, a characteristic that is one of the lens's strengths, aside from its color accuracy and contrast. The lens features a 7-blade diaphragm that may tend to produce somewhat angular bokeh balls rather than perfectly circular ones.
