Try some footage with the ISO (effectively, the film speed) set to 100 and the camera in auto mode. Take the bird up and maybe do a slow pan while recording. That would give you some varying light conditions to study. Shouldn't see much grainy effect on any normally lit day. BTW, are you looking at the video straight off of the SD card with it in your computer or at the video stored by the Go app on your tablet? The latter is a low res copy and doesn't really reflect how well the camera is recording.