ISO question

[PatrickD]

Why does the lowest ISO value for point & shoot cameras tend to be lower than the DSLR cameras? For example the canon A75 has an ISO range of 50 to 400, but the Digital Rebel is from 100-1600. Do DSLR's not need the lower settings?

[Lee Yuan Sheng]

Well, ISO 50 is awfully slow. I've shot with Velvia 50, and it was an experience that won't be forgotten (in terms of getting a decent shutter speed and the results afterwards).

Plus, Canon's IS O50 for the Powershot line tends towards ISO 80-100, so it's not really that low after all.

Another reason is that the smaller sensors have greater trouble with noise issues, so one way to sidestep them is to have an option for a lower ISO setting.