This guy will never stay still. I've never been able to get a good picture.
If you cover him with a box or a bowl he will calm down and maybe even curl into a nice shape then get your camera/mobile ready and whip the cover off - they usually stay still for a few seconds at least ...
No doubt. I have zero experience with them but they are impressive. I remember being a kid reading everything snake related I could get my hands on and finally getting to see one in some little reptile zoo in San Marcos. I love viperkeeper's Gaboon vids.