It was actually pitch black in Goblin Valley , Utah in this Spring shot. Within a ½ stop of -f4 with my exposures mainly of a 2 or 5 minute duration (I.S.O. equivalent 100). Technique practiced: experimental use of manual flash fired multiple times per frame, & usually, ( but I'm uncertain about this shot ) into a photographic umbrella (bounce flash) . Note : slight "star trails" are visable . More on Goblin Valley - visit my trails section list page- (scroll down to "E") or go directly to thegoblins.html