In digital photography , ISO means something entirely different—applied gain.Contrary common belief , thing “ sensor sensitivity ” light digital photography.The digital sensor always captures light basic ISO , light recorded , gain applied boost signal.For example , change ISO form value 100 200 , camera still captures image ISO 100.When recorded , camera ’ processor applies gain boost brightness image factor two.The increase brightness occurs cost details , sharpness , saturation , dynamic range , produces digital noise.This means , depending sophistication camera ’ image processor software algorithm , quality low light photographs vary brand brand model model.Because expertise designing camera image processors , Nikon ’ full frame cameras Fujifilm ’ APS-C cameras outperform Sony models using Sony sensors .