Nikon's fast full-frame fisheye — the manual-focus Ai-S 16mm f/2.8 for the F mount, 180-degree diagonal.
The Ai-S Fisheye-Nikkor 16mm f/2.8 is the faster full-frame fisheye in Nikon's manual-focus line, introduced at the end of the 1970s with the Ai-S standard. It opened the aperture to f/2.8 over the earlier f/3.5 design and became a long-lived optic that Nikon continued to offer for decades, filling the frame with a 180-degree diagonal image.
This is a manual-focus Nikon F lens with a maximum aperture of f/2.8 and a fixed 16mm focal length, built to the Ai-S standard for full compatibility with the metering and program bodies of the era. It covers the entire 24x36mm frame with a 180-degree diagonal fisheye projection and uses rear bayonet filters rather than a front thread. Details beyond the verified figures are omitted.
The character is the full-frame fisheye look with barrel distortion that curves peripheral lines, and the extra half-stop of speed helps in low light and with focusing precision. It suits action, interiors, event and creative landscape work where the bent horizon adds energy. Central placement of the horizon keeps it straighter when required.
On the used market this f/2.8 version is the most desirable manual Nikon fisheye and holds strong values, helped by its long production run and rear-filter system. Check the front element and coatings for scratches, look for internal haze and fungus, confirm the rear filters are present, and test the smooth Ai-S aperture action. It adapts readily to mirrorless and remains a favourite creative fisheye.