The D300 manual says that indicates that the camera is not detecting the memory card. Make sure a card is in it. If so, turn off the camera, remove the card, reinsert it and try turning on the camera again.a big E showing up in the control panel
Surely not just to get you to spend more money. Nikon wouldn't do that. Oooh, I know. They suggested the camera with the closest frame rate to what you are accustomed to shooting. You can just shoot it in DX crop mode and never know the difference... As the D300 is a DX camera and the D850 is FX I wonder why didn't they suggest a D500 ??