...and I was only using the old 70-300 VR and not my new 70-200/4.0 VR.
I was aiming at the spots on the tadpole's back through some glurpy pond water.
And was getting a lot of reflection off the water back into the camera.
Quite a bit of falloff though with this lens.
1. The scene.
2. Unresized crop of tadpole. It was a BIG tadpole. Must be a bullfrog.