Where to put the phone

The trace is only as good as the video. Five things make the difference.

1. Side-on. Put the phone level with you and at right angles to the direction you cast. From the front or behind, the rod tip moves toward the camera and its path can’t be read.
2. About a third of the frame tall. Closer and the rod tip leaves the frame; further and the tip is too small to follow. The dashed figure on the record screen shows the size.
3. Sun behind the phone. A thin rod tip against bright sky is hard to see. Turn so the sun is behind the camera.
4. Level. Prop the phone so the horizon is straight. A tilted phone tilts the trace.
5. The whole rod in frame, all the way through. Leave room above you and on both sides for the back cast and the forward cast. Turn the phone sideways for more room: tap Rotate for a wider view.

A plain background helps: trees, a hedge or grass rather than other people or moving traffic. Fill the frame with the caster, not with sky.