Yesterday morning I was about to head back to the house when I saw a large group of American white pelicans preening and sleeping in a huge clump. I pulled the ole M3 shooting blind into position to shoot when this handsome guy plunked down right in front of me to fish (alas he caught nothing):
Great blue heron landing. by
dcstep, on Flickr
Canon 7D, 1/4000th second, 500mm lens at f/4 and ISO 800 (it was very overcast, but if I'd had time to react I would have stopped down one full f-stop).
This demonstrates that nature photog should consider staying out when it's overcast. If you can get a close crop you can use +EV capture details that are hard to get in full sun. This setting is +1EV using AV mode.
This image would have been much harder in full sun because the sun is to his back and right shoulder. The contrast would have been huge and getting shadow detail on his underside (the real point of interest here) would have been hard. Also, believe it or not, the greys in the full sun would have risked blow out. This light is actually easier to work with than most think.
Dave