An hour or so ago, trying to find birds to photograph with the long lens, i was that the squirrel across the street was building its nest and snapped this series of photographs:
In the fourth frame the squirrel is looking at me as i think he could hear the camera clicking. I thought he might drop the leaves and run away but he didn't. I was curious about how he was going to get thru the fence as he was having trouble fitting the leaves under the bottom which is how he got thru as you can see further down. The last image is of the nest and you can see his (maybe its a her?) grey body to the right of the nest. There was a second squirrel working on the nest by taking leaves from the tree branches but she/he never was visible enough to photograph.
There were shot at 300 and 500 mm and seems quite sharp despite my hand holding the lens ... the image stablizer works really well.
I no longer have any doubts that this lens will provide me with the sharpness i want in a birding lens. However, it is quite heavy and creates a fatigue in my forearm muscles that, as i type, feels like carpel-tunnel syndrome ... that, i don't know what to do about. I do have a good mono-pod that would work as a leaning post but ... well, you know what mono and tripods do for cameras steadiness and, they also hinder the versatility of a sports/birding lens.
Oh well, i'll just have to figure that out.