Nikon's compact tele zoom — the manual-focus Ai-S Zoom-Nikkor 100-300mm f/5.6, constant-aperture reach.
The Ai-S Zoom-Nikkor 100-300mm f/5.6 is a telephoto zoom for the Nikon F system, introduced in the mid-1980s to the Ai-S standard. Its range from a short to a long telephoto at a constant f/5.6 aperture made it a compact reach lens for wildlife, sport and distant subjects in a single package.
This is a manual-focus Nikon F lens with a constant maximum aperture of f/5.6 across a 100-300mm zoom range, built to the Ai-S standard for full body compatibility. It operates with normal reflex viewing on the F system. Only the verified focal range, aperture and mount are stated; construction details are omitted to avoid error.
This telephoto zoom covers short to long tele framing with a steady f/5.6 aperture, keeping exposure and viewfinder brightness consistent across the range. It renders cleanly stopped down and gives useful reach in a manageable size. It suits wildlife, sport, travel and general telephoto work where portability and range matter more than a fast aperture.
On the used market the 100-300mm f/5.6 is common and affordable, a practical manual telephoto zoom. Inspect the elements for haze and fungus, check coatings, confirm the aperture blades are dry, and test the zoom and focus for smooth action without play. It adapts to mirrorless as a compact manual reach zoom, best used with support at the long end.