>>2670695sorry for poor englisherino,
1) Depends mostly on light pollution where you are. The general rule is, expose the longest possible without having star trails. Its the famous rule 500 divided by your focal length (for full frame) or else use 350 instead, for APS-C.
You want to gather the maximum amount of photons, so longest possible exposure, widest aperture, high ISO (if you plan to stack images -> stacking averages noise out)
2) Nice pics of milky way are composites of a lot of frames. Take a nice, in focus picture of your foreground (with light painting if necessary), and a separate long exposure, stacked version of your stars.
3) I use ISO 6400 and its fine if you stack a lot of frames, and use dark frames to help with the noise reduction. The more frames, the less noise in the final image (and the more signal and dynamic range obviously). In my opinion all great astro images are heavily edited. But of course I'm happier when my nebula (or whatever) looks great in my raw stack without too much editing. From my -modest- experience in astro, stacks with 100 frames (30 to 60 seconds) look great even at ISO6400. Stacks with only 10 images look like shit, even with dark frames.
But all of this if for deep sky, I've almost no experience in wide milky way shots.
