A4: 3D-Tracking Face-Detection; A5: 3D-Tracking Watch Area; A6: Number Of Focus Points - Nikon D850 Menu Manual

a4: 3D-Tracking Face-Detection

Choose whether the camera detects and focuses on faces when
3D-tracking is selected for AF-area mode.

a5: 3D-Tracking Watch Area

In 3D-tracking, the camera tracks subjects that leave the
selected focus point and selects new focus points as required
while the shutter-release button is pressed halfway. Choose
whether 3D-tracking uses data from the surrounding focus
points to track subjects that move even slightly from the
selected focus point (Wide) or tracks the subject based solely on
data from the vicinity of the selected point (Normal). Wide is
recommended for fast-moving subjects.

a6: Number of Focus Points

Choose the number of focus points available for manual focus-
point selection.
Option
1
55 points
2
15 points
108 Menu Guide
G button ➜ A Custom Settings menu
G button ➜ A Custom Settings menu
G button ➜ A Custom Settings menu
Choose from the 55 focus points.
Choose from the 15 focus points. Use
for quick focus-point selection.
Description