fordmondeo wrote in post #18616750
Any way you can simplify that for me?
That's way beyond my technical understanding of the world.
People tend to think of the noise at certain ISOs as something you experience in the out-of-focus areas at 100% pixel view on coarse monitors. That has nothing to do with the subject, though, which could be 12 pixels or 12 million pixels in size. I don't judge the usefulness of an ISO by how bokeh looks at 100%, sharpened, on a monitor. I judge it by what it looks like at the desired subject display size, with only necessary sharpening (which could be none, or even anti-sharpening with noise reduction). Higher ISOs are noisier to your final product when it means less light for your final image, but higher ISOs on almost all cameras mean less noise in the presentation of the final cropped image if it is because of higher optical magnification, rather than a loss of total subject photons. This may seem counter-intuitive, because higher ISOs normally give noisier results, if all you do is increase the shutter speed or stop down with *no* increase in pixels-on-subject. The fact is, most cameras will give you less "subject noise" with the same number of photons from the subject, at the *highest* ISO, because higher ISOs add less noise to a given number of photons, and usually only noisier because they are had in a context where there is significantly less total light from the subject or final cropped composition.