So, for everybody else, like me, who has nothing better to do on a Thursday evening than to take out-of-focus high-ISO macro shots of the inside of your lens cap...
...turn high ISO noise reduction to ON, and compare a shot taken at 0"8 with one at 1". The former will have the magenta lower-right corner, but the latter will have more noise overall.
What will this demonstrate?
Why, of course, that you, like me, need to get a life. Or, at the very least, find (or make) some decent light to shoot in, and at least a marginally more interesting subject.
Hmmm...that bit of lint on the napkin looks interesting...I think I'll break out the MP-E, see what it looks like at 5x, wide open, slightly off focus, tilted at an odd angle, ISO 12,8000, handheld, by the light of my iPhone. Underexposed, of course, and then pushed five stops in DPP. Look out, Getty -- here I come!
Aw, damn. The cat just sat on the napkin. Guess I'll have to go look for a more interesting piece of lint for my Magnum Opus Maximus!