bsamoy: I am not saying don't use ISO400, I say don't use it when not necessary. ISO400 with shutter speed 1/3200 don't make sense... to me. But by reading your comments I am wondering if I am alone think this.
You are not alone, I agree with you.
BUT, I also understand that sometimes (and we must all be guilty of this on occassion), when the camera is set on a previous setting, or even in auto, and you have a split second to take the shot I'd rather get something than nothing. Just point and shoot, then if you have time have a look at the meter, change the values and have a go again.
I remember not so long ago (3 years as it happens) sat in a thrid floor hotel room choking on smog. The sun had set and the streets came alive, trying my hardest to pull my ISO800 film back with a film picker so I could load it for some night shots of the market. Sometimes I just couldn't get it and gave up and loaded a new film!
How often do we actually change our ISO? I know that we can do it far more quickly and easily with digital (one of teh reasons for me changing to digital), but I tend to leave my camera at ISO 100 (or 200 now with the D300) and work with that as my walkaround. I can usually find a shutter speed and aperture to suit.
The only time I change the ISO is when I'm set on composing specific images such as landscapes, sunsets, wildlife etc, or like today when I'm heading out to take a photo for a magazine cover when I'll choose the lowest ISO possible and use filters if needed.
As I would have selected a film for such images I select the ISO setting on my camera. I certainly don't mess about changing it for every shot and I'm wondering how many others do this? Or do you change your ISO for every shot?
The joys of digital ![Confused [8-)]](/emoticons/emotion-43.gif)