I love a good sharp shot like many of us, and I’m not worried about raising the ISO on my camera to get it. Current cameras are a marvel of electronics, giving us the ability to easily capture shots that weren’t possible ten years earlier. So I’m often left questioning the wisdom of long established photographers who just can’t seem go beyond ISO400.
It’s absolutely true that noise increases and becomes more visible as ISO rises. Since the first EOS D30 DSLR launched in 2000, CMOS image sensor technology, and noise reduction processing tools have seen major advances. This means that while you might have had a bad impression from ISO1600 film, you shouldn’t avoid ISO1600 on a digital camera. My own recollection of ISO1600 print film was grain that was visible on 6x4 inch prints.