ISO Expansion Question

I was looking at my 40d and I was wondering why the ISO expansion was in the custom functions. Why didn't Canon just make 100-3200 default? I'm thinking it has something to do with the frame rate/buffer if the camera has to shoot at 3200.

Can anyone enlighten me?

The higher the ISO, the noisier the image. Where do you draw the line between an acceptable level of noise and an unacceptable level? Why not have ISO 10,000,000 and produce images that look like those magic eye pictures? Apparently, Canon feels that ISO1600 is the max acceptable level on that camera but provides the option of going one stop higher for those who know what they're getting themselves into.

The reason it's not default is because ISO 3200 is not a native ISO on the 40D. ISO 3200 on the 40D is really an ISO 1600 shot pushed in camera +1 stop to 3200 via software rather then hardware amplification.

tfd888 wrote in post #11005530
The reason it's not default is because ISO 3200 is not a native ISO on the 40D. ISO 3200 on the 40D is really an ISO 1600 shot pushed in camera +1 stop to 3200 via software rather then hardware amplification.

This..