Autofocus, set up right
How do you set up autofocus and subject detection on a Nikon Z8 so it holds your subject?
AF-C for movers, AF-S for still life
AF-S locks focus at the half-press, and by default the camera will not fire until focus is achieved (focus priority). AF-C tracks continuously and, by default, fires the moment you press (release priority). There is no AF-A on the Z8 — Nikon makes you choose, and anything that moves gets AF-C. AF-F exists too, but only in video mode, where it focuses full-time.
Name the subject
Subject detection offers Auto, People, Animal, Birds, Vehicle, Airplanes, and Subject detection off. Vehicle is a single category on this body — cars, motorcycles, trains, airplanes and bicycles are all detected under it. Animal covers dogs, cats and birds, faces first and then eyes; Birds is also a dedicated category with its own behaviour for feathered subjects. Auto gives priority to people, then animals, then vehicles and airplanes. Remember: the Video Recording Menu keeps a separate detection choice of its own.
Pick — and size — the area it hunts in
Wide-area AF (S) and (L) are the everyday areas. Wide-area AF (C1) and (C2) are the flagship's own: custom areas whose size you set by holding the focus-mode button and pressing the arrow keys — match the zone to the subject. 3D-tracking follows a subject you place the point on, across the whole frame; Auto-area AF searches everything. Dynamic-area AF (S/M/L) backs up a chosen point with its neighbours for predictable movers, and Pinpoint AF is the still-life specialist — a point smaller than Single-point, AF-S only.
Tune blocked shot response
Blocked shot AF response sets how the camera reacts when something passes between you and your subject in AF-C. Toward 5 (Delayed), it holds on to your original subject through the interruption; toward 1 (Quick), it happily shifts to the crossing object. Note the fine print: with 3D-tracking selected, the behaviour is fixed at 3 regardless of this setting.
Speed, and the frames before the moment
Continuous high-speed stills run at 20 fps; high-speed frame capture + adds C15, C30, C60 and C120 (JPEG) — feed it CFexpress or XQD cards rated at least 250 MB/s, as Nikon recommends. Pre-Release Capture buffers frames while the shutter is half-pressed and, on the full press, saves frames from just before it; the pre-release burst length is set at d3, and standby lasts up to 300 seconds.
Set AF-C, People, Wide-area AF (C1) sized to a person — then 3D-track them crossing the room and feel the point travel. That is the setup working.