Hi! As stated in the 'Title', I am new to this so please be patient! I recently aquired a Nikon D300 and can't wait to start using it. I read my manual, charged my battery, set up my functions, and put on my lens. Sounds good, right? Well, I can't get an exposure I press the shutter release, and nothing. I took the lens off, and yes I got an exposure. Any ideas?