those are really beautiful! I especially like the shot with the golden gate bridge...would be interesting to see a panoramic shot of the city from where you shot the first 2.
Nice shots but they do look a little dark on my monitor. Just a note on ISO and exposure time, Using ISO50 you are limiting your dynamic range by 1 whole stop. The camera takes a 100ISO shot and darkens it by 1 stop thus reducing your dynamic range so i would avoid using it as much as possible. Last of all I try and keep my exposure times below 60 seconds for this kind of thing as 'dark noise' and hot pixel noise become more apparent after this time.
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