Quote Originally Posted by subwaybuff
I use a digital camera- an Olympus C-50. I have no adjustment for "film speed" :-)
Not entirely true. The C50 has a variable ISO from 80 to 320 This can be set to change automatically or you can manually set the ISO.

Even though this site specializes in analog photography and we tend to not discuss our digital toys based on my own experience I would stick with manually selecting your ISO speeds. Lower speed = less grain. But for lower light situations you end up using higher ISOs and sacrificing quality in order to get the shot at all.