GH2 vs GH3 - Long Exposures and Astrophotography (Test shots inside)

Anders W wrote:

OK. So these are intended to be black-frame shots with the lens covered by the lens-cap or what? And in completely dark surroundings or not?

When doing such shots, I always take the extra precaution of a) going into a very dark room and b) using the smallest aperture possible (rather than f/1.4) since there's always a possibility that some photons find their way in, especially at shutter speeds as long as one minute.

Of course I can't be sure that problems of that kind are responsible for the visible difference between your two shots and I am, as I said, prepared to believe that the GH3 does better. But a more interesting test of that would be to shoot a bright object (take some street lamps if the stars aren't visible) against a dark background and then match brightness as well as contrast. In the shots you show, that from the GH2 is for whatever reasons visibly brighter than that from the GH3.