HOW DO WE DETECT "NOISE" IN A PHOTO?

We detect noise by seeing it - it's simply there for the eye to see.

I don't look for noise, but when it is there, I see it . . . and it ruins the photo for me. I think it is just so horribly ugly it distracts me from any beauty that might be in the image. Think of a McDonald's bag littering an otherwise gorgeous landscape photo - it would be a terrible distraction that would ruin the photo for most viewers. Well, that's what noise grain does for me. I wish Canon and all of the other manufacturers would find a way to simply eliminate it altogether.

SMP_Homer wrote in post #15926598
There are a lot of ladies in these forums.. Even though your intentions are probably positives, probably best to not start your posts assuming everyone is a Sir...

But perhaps he had the foresight to check out that person's personal website, and saw that his first name is David. It is rather reasonable to assume that someone with a first name of "David" is a Sir.

If you are going to pick on the OP (who seems to be a very nice, respectful guy), then do so for this post being in the "Canon EF and EF-S Lenses" forum.