Overall photo quality from the S9100 is very good, on par with most other cameras in its category. Though its sensitivity settings run from ISO 160 to ISO 3200, the S9100 produces the best results below ISO 400. regardless of sensitivity, photos generally look somewhat soft and benefit from sharpening with photo-editing software. There's a Fixed Range Auto option that will limit you to ISO 160-400, which is nice since, again, this is where the S9100 performs best. On the other hand, the regular Auto ISO setting only goes up to ISO 800 and since the S9100 does OK there, too, it's fairly safe to use. The two highest ISOs--1600 and 3200--should probably only be used in emergencies, mainly because the colors get very washed out and the noise reduction makes subjects appear smeary.