By incident today I shot a sequence of photos with exposure-bracketing left on. It was set to 3 shots -2EV, 0EV, +2EV.
As I tried to save the over and underexposed shots (from RAW in captureNX) I was quite surprised:
- I had one shot at f5.6 1/20 sec, ISO 1600
(!); this was the +2EV over-exposed one. This one was clearly in the danger-zone, ISO-wise.
- and I had one shot at f5.6 1/45 sec, ISO 200
; this was the -2EV underexposed shot. This shot had received only half the light of the other shot but was very much in the ISO-comfort-zone.
My assumption now was, when I corrected both shots with +-2EV in CaptureNX that the second shot would turn out fine and the ISO 1600 shot would be lost, due to noise.
Boy was I wrong! On a nice low-contrast patch of background, the underexposed ISO-200 shot came up with very visible noise after correcting +2EV, while the overexposed ISO-1600 shot almost had no grain
It just looked like the ISO-values were reversed, so krass was the difference in noise.
The only thing that could not be saved were the highlights from the overexposed shot.
Well, you live to learn
Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews
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