Originally posted by chadci At the risk of sounding ignorant, how much ISO does one really need and at what point is it just diminishing returns?
It really depends on your photography interests.
As someone Coming from film, I mainly took photos at ISO100-200, no more than ISO 800.
As the low-light High-ISO capabilities of dSLRs improved dramatically, I have become more and more interested in low-light and available-light photography.
There are plenty of real-life situations where usable ISO6400 would be very welcome. Museums, Indoor performances without flash, all kinds of Indoor activities....you name it.