... at 300mm straight out of the camera with the Nikon 28-300mm lens.
At 1200mm straight out of the camera with the Nikon 600mm F4 lens and 2x teleconverter.
Yes, I took Aaron's suggestion and bought a 2x for the 600mm lens. It seems to work pretty well as long as your subject is "contrasty" against the background. The autofocus seems to be about 10-20% slower than normal but well within working speed for shooting whales or a slow moving subject.
Aaron has been teaching me some astrophotography tricks for a project I have planned. We spent about an hour the other night shooting across a neighbors pond when the full moon was coming up. I was even lucky enough to catch a shooting star just above the moon.
Somewhere out there a little gray man is wondering why I am laying on the ground in the cold taking pictures of the sky. Seeing the stars on a full moon proved difficult but we wanted to see how the FX sensor compared to a DX sensor on night time shots.
"Painting by Moon Light"
This is actually the moon, can't you tell?
While walking back to the house the other night Aaron accidentally hit his shutter release and decided since it was set on a long exposure he would move around a little and see what happened. I couldn't let him have all of the fun so like a couple of goobers, we were both swinging our expensive cameras around in the air and laughing our heads off.
My wife said we were acting like a couple of three year olds. That's a good thing, right?