Originally posted by normhead True, and I have always said, good pictures don't come from high ISO. Yet people continue to harp on the benefits of high ISO images. In these discussions, minute bits of resolution are proclaimed to be worth switching brands for, while larger issues like the loss of resolution due to increased noise, loss fo Dynamic Range and colour depth are ignored as if they don't exist.
Back in the day (k-5 vs D800) I posed the question "How can you compare high ISO settings and claim one is better than the other, when at 100 ISO they are practically identical and the high ISO image is never as good as the 100-400 ISO image?"
The question has never even been adressed though asked a hundred times. When high ISO comes with the same dynamic range, colour depth and resolution as lower ISO images, I may be more inclined to pay attention to these things.
But to be blunt, the argument is over which crap image is better, when any neutral observer would say, I'm not switching brands so my crap images will be slightly better than someone else's crap images. I trash all crap images. And I certainly don't make camera purchasing decisions based on them. The only thing that matters to me is what is the highest ISO I can get a decent image from? That's gone from 400 ISO with the K20D to 3200 ISO on the K-1.What happens at 102,000 ISO is of little interest.
Sometimes a low ISO image is simply impossible. The photographer has no tripod, they can't use a flash, the lighting is low, subject is moving, a small aperture is needed to get DoF.
It's night 50% of the time of this planet, it's cloudy much of the time, people are indoors most of the day, it's usually dim on the forest floor, most scenes contain stuff a range of distances, and lots of stuff moves. And then there's need for high DR which is just as much a problem at sunset as at moonrise.
Bottom line is that the majority of all the possible photographs one might take in this world require higher ISO (and high DR at all ISOs). For most of the history of photography, photographers could not take photographs except in ideal sunny f/16 conditions because film was notoriously insensitive to light (film wastes about 97% of the light). Early digital cameras were worse than film in this regard. It's only in the past few years that the equipment has improved.
But most photographers are still locked in a mindset driven by the inadequate equipment of the past. Most photographers think they don't care about 102,400 ISO because they never take 102,400 ISO pictures. But they never take 102,400 ISO pictures because they don't have equipment that can take 102,400 ISO pictures. They unwittingly lose most of the pictures they could take because they believe such pictures can't work. But that's changing.
I, for one, care about 102,400 ISO because I know how many more photos I could take, how much more freedom I'd have to pick narrower apertures or faster shutter speeds, and how much more DR I could get from all ISOs.