I just filmed a Rugby tournament last month. I hate working in 4K as a rule but it was perfect for a sports event.
Funny... I'm a sports photographer here in RI and I have been shooting a local rugby team for their last 3 games... thought about using my Phantom, but I hate to be a distraction. I guess I could have shot in 4k with the GoPro and zoom in to 1080p as you did.. wish I thought of that...
