Canon DSLRs (or at least the ones I have used), when in Program, Aperture or Shutter modes will refuse to take the shot when [...] I'm guessing the Nikons and other DSLRs behave similarly ?
I noticed that too, but was not sure if I was doing something else wrong. It is a bit annoying, I have to say. Again, I guess that one gets used to that. I too have only used Canon DSLR, though, so I don't know how Nikons behave.