Getting a phone tripod to actually stay still

A tripod extended to its full height is at its least stable. That is physics, not a fault.

Extend the thick sections first

Leg sections get thinner as they go down. Use the upper, thicker sections first and leave the thinnest ones retracted unless you truly need the height.

Leave the centre column down

Raising the centre column puts the load above the point where the legs spread. It is the fastest way to make a stable tripod wobbly.

Spread wide, and weight it

Legs at full spread beat legs at a narrow angle. If there is a hook under the centre column, hang a bag from it — even a light one damps vibration noticeably.

Phone holders

Check the clamp range against the width of your phone with the case on. A clamp at the very end of its range holds with almost no spring pressure left, which is when phones fall out.