Nikon's rare rectilinear ultra-wide — the manual-focus 13mm f/5.6 for the F mount, distortion-corrected.
The Nikkor 13mm f/5.6 is a rectilinear ultra-wide-angle for the Nikon F system, introduced in the mid-1970s and produced only in very small numbers to special order. Unlike a fisheye, it corrects straight lines to stay straight across an extremely wide field, which made it a demanding and costly design aimed at architecture and technical photographers.
This is a manual-focus Nikon F lens with a maximum aperture of f/5.6 and a fixed 13mm focal length, engineered for rectilinear geometry rather than fisheye projection. It uses a rear turret of built-in filters rather than a front-mounted thread because of its large curved front element. Given its rarity, only verified figures are given; construction specifics vary by source and are omitted.
The rendering is defined by its near-total control of distortion at an extreme angle of view, holding architectural lines straight where lesser wides would bow them. It suits interiors, cityscapes and technical documentation where geometric fidelity matters more than speed. The modest f/5.6 aperture reflects the difficulty of the correction rather than any shortfall in intent.
On the used market the 13mm f/5.6 is among the most sought and expensive manual Nikkors, changing hands rarely and mostly among collectors and institutions. Inspect the large front element for scratches and coating wear, confirm the internal filter turret operates, and verify the aperture and focus are clean and smooth. Its value and scarcity make it a collector piece rather than a working tool.