Nikon's constant-aperture standard zoom — the manual-focus Ai Zoom-Nikkor 35-70mm f/3.5 for the F mount.
The Ai Zoom-Nikkor 35-70mm f/3.5 is a standard zoom for the Nikon F system, introduced in 1977 with the Ai coupling. Its range from a mild wide to a short telephoto made it a natural walk-around lens covering the everyday focal lengths, at a constant f/3.5 aperture that kept exposure consistent across the zoom.
This is a manual-focus Nikon F lens with a constant maximum aperture of f/3.5 across a 35-70mm zoom range, carrying the Ai aperture-indexing coupling for full-aperture metering. 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 constant-aperture standard zoom renders cleanly for its era, with good sharpness stopped down and a range that covers wide, normal and short-portrait framing. It suits travel, street, general shooting and casual portraits where a single flexible lens is wanted. The constant f/3.5 aperture simplifies manual exposure across the range.
On the used market the Ai 35-70mm f/3.5 is common and affordable, a practical manual standard zoom. Inspect the elements for haze and fungus, check coatings, confirm the aperture blades are dry, and test the zoom and focus for smooth, tight action. It adapts to mirrorless as a compact, versatile manual standard zoom.