I'm still kicking myself about this shot. I messed up. I'd taken a few shots of the adder as he basked motionless in the sun. Then just as I finished and moved back a little, he did a huge yawn, revealing those fangs. By the time I'd found him again in the viewfinder he'd started to close his mouth (it was wider than this!), and my aperture setting was inadequate. One of those shots that look great on the little preview on the camera, but result in disappointment as soon as they're reviewed later.