Hi Hugh,
Yes, there are camera control commands in DroneBlock. They aren't extensive, but they are there. Some gimbal control commands as well as switching from video to photo mode, with commands that let you set how many still shots you want to take, or how long you want the video to run. I didn't dig too deeply, because the
Tello itself is somewhat limited, and I'm still trying to program flight paths that work. No fault of DroneBlocks. Since the
Tello doesn't have proximity sensors in front, or to the sides, I'm trying to get a course that flies around the house without hitting something. I've run courses out in the yard, and it seems just fine. DroneBlock is free, so if you have an iOS device you can download it and look it over. I looked over the release notes, and the developers seem to be extremely responsive to requests. If there's a command you need, you can log a request and see what they say.