Auto-Focus, Depth of Field and Aperture
Depth of field (DoF) refers to how much of a scene is in focus.
Aperture controls how much light is let in through the camera hole. Usually measured in f-stops, i.e. a fraction like f/N, where a small N means a bigger hole, or wider aperture. Wider aperture creates a shallower DoF, which keeps a smaller part of the scene in focus. A narrow aperture, i.e. a higher f-Number, or bigger N, will keep more of the scene in focus.
Longer focal lengths (i.e. with a telephoto lens) means shallower DoF, i.e. smaller part of the scene in focus.
Auto-Focus (with the Nikon Z50 ii)
https://www.kenrockwell.com/nikon/z/z50-ii-users-guide.htm
Auto Focus (AF) is how the camera zeroes in on a subject. There are different ways to do it, hence a selection of AF modes on the Nikon Z50ii.
AF modes are
- AF-S (static, for subjects standing still)
- AF-C (continuous, for moving subjects)
- AF-A, which switched between the above dynamically
On the Nikon Z50ii, the AF modes are accessible from the Fn2 button out of the box, though you can change that. Otherwise you can get the modes from the Menu, under Shooting/Focus.
Press the Fn2 button, and the rear dial cycles through the modes.
The front dial cycles through the AF Area modes. The guy in the link above disables all the AF Area modes except for All Area AF (selects AF area automatically) and 3D which focuses on a single area.