The new lens provided me a glimpse at a very cool feature of that Blue Heron that I was shooting the other day... Its nictitating membrane.

A nictitating membrane (yeah, I know that is a hard word to stay) or sometimes referred to as a third eyelid is a semi-transparent lens that certain animals have to protect their eyes. I've seen them on lizards, frogs, and birds... but even some mammals have them. Basically they act as a way for the animal to still be able to see in conditions that might damage their eyes. In a heron's case that would be likely when they're stabbing their beaks into water to catch prey.

I could see this heron blinking his nictitating membrane and managed to get several sharp photos showing it. These are cropped at 100% just to show the effect, but they also do a decent job of showing the sharpness achieved with this new lens.

Open	Half-way	Closed

Technical Data:Canon EOS 7D, Canon EF 100-400mm f/4.5-5.6L IS II USM at 400mm, 1/320 sec at f/8. ISO 320. IS Mode 1. RAW processing and cropped in Adobe Camera Raw.

Cool stuff, no?

- Bill