I am trying to decide whether to upgrade my D80 for the D300 or buy a 300 2.8 AF. A used 300 2.8 AF would be about the same price. This is my price limit. I currently use a 70-300 VR and find the sweet spot for sharpness at 300mm about F8-F9. My interest is Birds, and lately have been trying BIF. I am having a hard time with getting a high enough shutter speed and find that i don't care for the noise above iso 400. I usually crop 50-60%. Also I could use a better focusing system. What can I expect from the D300. WIll this help enough or should I go for the 300 2.8 AF. Note I do not have any other telephoto lenses at this time, and just a cheap tripod.