Thanks for the flattery, Kurt :P. I use flash 9 times out of 10. All in all, I would imagine it's not a wonderful experience for the frog, but it can't be too bad - I've photographed lots of calling frogs and toads over the last few years, and most usually go right back to calling after being flashed at (look towards the bottom of this gallery for examples). Same goes for eating - the African Bullfrog in my avatar got flashed about 50 times in a few minutes but kept on eating and performing.