We went to Tubac to see the Christmas luminaries. Here, I wanted to capture the boots with some light painting. I decided to try my smart phone for the light source. A couple of shots were really bad - I had forgotten that the front of the phone was also visible and I got large intruding light streaks.

This one is "Almost" perfect, except for the lower left phone streak.
Later I switched to a small penlight and got what I wanted.