bent toe wrote in post #17328884
Hmmm, i thought the opposite, high iso is only used at night or in very poor lit places.
I could be wrong and if so, what are some good reference high iso photos then?
Using a slow lens or stopped down for a sweet spot or DOF, with high magnification and the high shutter speeds needed for that magnification, I have needed ISO 25600 in the middle of a sunny day, under the green canopy. Same near dusk and dawn, out in the open. Now that cameras are getting better at high ISOs, people are opting to shoot with the shutter speeds and f-stops that they really want, with less regard for resulting ISO.
Each of the three RAW color channels is actually shot at its own ISO. The ISO setting that the camera expresses is the ISO of the green channel. For most digital cameras, if the camera is set to ISO 1000 and the white balance is Daylight, the ISO of the blue channel is about 1400, and the ISO of the red channel is about 2000. In incandescent light, that would be about 1000 for the red channel, and about 4000 or even more for the blue channel, depending on how warm the light is. For deep desert shade, the actual red ISO is 6000 or more, and in deep green-filtered foliage the red ISO can actually be quite high, too. This is why even a tiny bit of fill flash helps a lot with red noise in such situations; even a -3 FEC could nearly double the red light!
So, ISO is not ISO, if you're going strictly by the camera setting, as different white balances result in different ISOs for the red and blue RAW channels. Combined with differences in contrast and key of the scene, even more inequity exists. You can compare two cameras at the same ISO in the same scene, but comparing one camera against another, or one ISO against another ISO on the same camera is meaningless if the scenes don't have the same WB and tonal range.