Minimum ISO setting on dig. cameras

[arclight]

Why is the minimum ISO setting on digital cameras generally 100 ?

It may be that image quality cannot be improved below that speed.
However, from a creative aspect, it could be useful if a greater range of lower ISO settings could be selected e.g. 50/25/12/6/3/1 thereby avoiding the need to use ND filters on occasion.

 

[admirable]

Canoon 1d minimum is 50, but hardly used in this country

 

[Canon Bob]

ISO is modified by adjusting the sensor gain...go too low and things are likely to lose linearity.

Bob

 

[desantnik]

Its 100 (or even 200 on the D300!) because that is the baseline for the sensor. ISO 100 is generally the slowest you need to go. If you moved the baseline to lower, you'd loose the high end.

Going slower won't be useful to many, ND filters are a much better way for long exposure stuff, which really is about all you need less than 100 for.

BTW also, the "lo" (and "hi") ISO settings on cameras are a software cludge... you will loose dynamic range at the low end and add stupid amounts of noise at the top end....

 

[arclight]

Thought there would be a snag.
Thanks.