Definitely the closest I've been able to get to a bull frog.
All but this one particular one jumped/dove often before I could see them. So for this one, I started to belly crawl (like how the military trains recruits to crawl under barbed wire - I suppose) and kept getting closer and closer. Finally, with only the 300mm (no tubes nor 2x), I had my chest over the bank with my head sideways, the camera about 3" from the water, and my right elbow in the pond. Shot at about the closest focusing distance of my lens.
Oh, my satisfaction came a few minutes later when another father came along carrying a butterfly net with his two young boys. I watched him try to nab this same frog and almost fall into the water as the frog made his escape At least I got mine!