Depends on the size of the subject. Also the available light and contrast and background play a role.
For a small object you need to get quite close for it to pick up and it will lose it again pretty quickly.
Active track is not very reliable. Please be prepared to switch it off immediately when things seem to go wrong. Keep your eye on the drone all the time.
Active track destroyed my MP the first time I tried it. Wasn't my fault. It lost the subject and as soon as the subject stopt moving the MP found it again and crashed with full pitch into the stationary subject. DJI gave me a brand new one. But still, I never trust it again.
