Nikon's ultra-wide Ai-S — 18mm f/3.5 manual-focus prime with extreme 100° field of view.
The Nikon Nikkor 18mm f/3.5 Ai-S is a manual-focus ultra-wide prime providing 100 degrees of field of view on full-frame. The 18mm was Nikon's widest rectilinear prime before the AF 14mm. CRC (Close Range Correction) system.
Optically good — CRC improves close-focus performance. Sharp from f/8 with the 18mm providing dramatic ultra-wide perspectives. The f/3.5 is moderate for ultra-wide. Manual focus with smooth Nikon helicoid.
Nikon F mount with 72mm filter thread. Approximately 330g — compact for 18mm. Ai-S coupling. Full-frame coverage with 100° FOV. CRC system. Minimum focus distance 25cm.
Available used at mid-range prices. The AF-S 14-24mm f/2.8G and Z 14-24mm f/2.8 S are dramatically better. Works on Z via FTZ with focus peaking. For vintage ultra-wide enthusiasts. A characterful manual ultra-wide for adapted use.