I'm considering a panasonic or a nokton 25mm lens. I tried photographing the night sky before - with poor results. I tried with a olympus 12mm and got much better results then I've had before. I'm now looking for a 25mm lens, and wonder if F.95 to F1.4 is a big step in night sky photography. Will F.95 allow a much shorter exposure time then F1.4? The longer the exposure the more the stars will move. I'd prefer AF and the lighter weight of panasonic, but will the 1/2F stop make a big difference?