A quick tip for photographing at night to calculate a good exposure. First set you cameras ISO to 6400. This is just for exposure calculation. You won't be take long a photo at this ISO. If your light meter reads a 1 second exposure at ISO6400, then that equals 60 seconds at ISO100. 2 seconds = 2 minutes And so on. This is just a guide. You might need to exposure a bit shorter or longer depending on how you envision the photo turning out. You would want to take a photo at ISO100 to avoid the severe grain at night that you will get with a higher ISO. Basically it's a 6 stop difference in light between ISO6400 and ISO100 (1 second and 60 seconds respectively).
