on the left, cropped centre image at 6.3. On the right F4.
Nikon have never said (nor have I I think

) that these lenses wont work with the D300.
However, I asked Nikon, as ALL my lenses exhibit the SAME problem, could it be a fault in MY D300.
Their answer was:-
"I can confirm that any lens, including the 300/4 and 500/4, will be somewhat less sharp wide open than stopped down 1 or 2 stops. The degree of image degradation depends on the particular lens design, however the more expensive, professional lenses tend to have this effect minimised. I would strongly suggest to loan the 500/4 and try it before the purchase."
Having said I didn't want to spend £4,000+ on lens I can't use for the purpose it was bought for (500mm F4 VR).
I also mentioned I recently shot with a Canon 40D and 500mm F4 and saw no major degradation at max. app.
Might still take it in for a general service and see what comes up. Thats why I asked for a sample image from you guys. So I could compare and see if I was expecting to much.
regards.
Stu.