Once upon a time, all the way back in 1959 to be exact, Japanese optics firm Nikon released its F-mount to attach lenses to SLR film cameras. Over time, it improved it, adding autofocus, strapping it to the front of digital cameras and releasing new lenses, until the Nikon D6 in 2020 became the final camera to receive the mount.
The reason for this? The Z-mount. Nikon’s mirrorless lens mount was introduced in 2018 with the first Z-series cameras, and improves over the F-mount in many ways. Not only is its diameter larger - 55mm vs 44mm, making Z the largest full-frame mirrorless lens mount - but it comes with 11 electrical pins for supplying power and sharing data with the lens. This leads to excellent autofocus, and the potential to produce lenses with very wide maximum apertures. Older F-mount lenses can be used on Z-mount cameras with an adapter, though those that rely on a motor in the camera body to power their autofocus will be manual-focus only.
