As they are Nikon’s first full-frame mirrorless cameras, the Nikon Z 6 and Z 7 introduced a new autofocus (AF) system to get to grips with. This is also present in the new APS-C format Nikon Z50.
Unlike Nikon’s DSLRs, the Z6, Z7 and Z50 rely on a hybrid AF system. This means they use both phase detection and contrast detection. However, as they have different sensors with different pixel counts, they don’t have the same number of AF points.
The 45.7Mp Z 7 has 493 AF points and the 24.5Mp Z 6 has 273 points. In both cases, these AF points cover approximately 90% of the sensor. That means that you can focus closer to the edges of the frame than with a Nikon DSLR like the D850. Similarly, the Nikon Z50 has a 209-point hybrid AF system and the points cover 90% of its imaging area.
Single, Continuous and Full-time
As with Nikon DSLRs, the Z 6, Z 7 and Z 50 have Single (AF-S) and Continuous (AF-C) autofocus modes. As usual, AF-S is designed for use with stationary subjects whereas AF-C is for moving subjects.
Another mode, Full-time AF mode is available for shooting videos. When this is in operation, the camera adjusts focus continuously when the subject distance changes. However, it locks the focus when the shutter button is pressed half-way.
You can select the focus mode that you want to use via the ‘i’ menu. Alternatively, by default, press and hold the Fn2 button on the front of the camera while rotating the main command dial.
The command dial is the dial on the top of the camera near the thumb rest.
The Z6, Z7 and Z50 allow you to select the AF point you want to use individually or in groups using the AF-Area modes. These options can be found in the ‘i’ menu, the main menu or by pressing the Fn2 button while rotating the sub-command dial.
The sub-command dial is the dial near the top of the grip, beneath the shutter button and power switch.
Single AF mode
In Single AF mode there’s a choice of Pinpoint AF, Single-point AF, Wide-area AF (Small), Wide-area AF (Large) and Auto-area AF. Pinpoint AF and Single-point AF let you target a small area in the frame. Pin-point AF is a little more precise than Single-point, but it can be slower and is only available for stills photography, not video.
The Wide-area AF modes give you a larger area for focusing than Single-point AF. Using the Small setting allows you to target the subject more closely than the Large option. The Large setting is useful when the subject is hard to distinguish in the scene.
When Auto-area AF is selected the camera attempts to find the subject automatically. By default, it will defer the focus to a face in the scene. If multiple faces are detected, you can use the multi-selector control (navigation pad).
Continuous AF mode
The available Area-AF modes change when you switch from Single AF to Continuous AF mode. The options include Single-point AF, Dynamic-area AF, Wide-area AF (Small), Wide-area AF (Large) and Auto-area AF.
Single-point AF, Wide-area AF (Small) and Wide-area AF (Large) modes work as in AF-S mode, but the focus adjusts for as long as the shutter button is depressed.
Dynamic-area AF mode allows you to set the location of the focusing, but the camera will use the information from the surrounding points if the subject moves from the selected area. This makes it easier to keep a fast-moving subject sharp than Single-point AF as you’ve got a bigger target to keep over the subject.
Auto-area AF mode is useful for subjects that move erratically. It can be used to detect and track subject automatically, but there’s also an excellent Subject Tracking mode that is activated by pressing the OK button in Auto-area AF mode. When the white tracking point (box) appears in the frame, you just need to position it over the subject before pressing the OK button again (or AF-on). This turns the white subject-tracking box yellow, as shown in the image below.
The camera will then try to track the subject around the frame. It can also do this in AF-S mode, but in AF-C mode it adjusts the focus as subject distance changes.