Same and thanks. But on another note you can use the Exposure and flash compensation that is built into most cameras. Look for that before you go and lose your DoF. Take that advise from me and Zennon and run, it will help you out with night shots a whole lot. Also, you might not notice Noise with your camera on ISO levels that are high but once you start doing post processing on them you will bring it all to life. ISO is a trained camera man/woman's last fall upon.
You can adjust so much more... white levels, exposure, aperture, exposure comp, flash comp. The last thing you fall on is ISO in my book. =) Hope that helps
Same. The camera can judge light variables very well during the day but aperture is DoF and is user based opinion per shot. So you should look at that, and again look on the stickies etc, there are some good tutorials.