Where the phone goes

Behind the baseline, centred, about head height or a little above. The whole court in frame, including the far baseline — that line is the one we measure everything against. Wedge the phone against a fence post or use a clamp; a friend's hands are the most common reason a session fails.

Table tennis is the exception — film side-on, level with the table, two to three metres back. From the end you lose the bounce.

The camera screen shows the court guide live. When all four corners go green and the badge says LINES LOCKED, you are set. If the corners go clay, the guide tells you which way to move before you waste a recording.