Originally posted by attack11 who told you that?
thats how digital light sensors work, period.
Originally posted by attack11 you've never done this apparently, so why are you guessing at how it works?
no i havent, because its a silly idea.
Originally posted by attack11 regardless, it won't stop you from getting absolutely horrible noise in the dark once you shoot above iso1000
please refer to examples below:
since you're alot like me, and unless you either do it or have someone show you something, taking someones word for whatever is difficult.
so here are some very controlled tests for your pleasure.
all done off a tripod, with mirror lock up, Pentax FA43 at f4.0 manualy focused.
FIRST ROUND:
ISO 1600 VS ISO 800 PUSHED.
camera meters for 1/6 seconds, therefore both shots are done at 1/6 to underexpose the 800.
iso 1600
iso 800 + 1ev in lightroom
even at +1ev in lightroom the shadows dont fill as much as iso 1600, there is more black in the underexposed shot, and rightly so, noise in my opinion is identical.
ROUND TWO, more extreme.
ISO 3200 VS ISO 200 PUSHED 4 stops
metered at 1/10 for iso 3200
iso 3200
iso 200 exposed 4 stops in lightroom
as you can see, ISO 200 pushed still amplifies some noise in the areas where there was some noise hiding, but overall, nothing happened, why?
because you cant increase the signal of something thats not there!
ROUND THREE, reverse fight
ISO 200 underexposed 4 stops in camera VS Properly Exposed ISO 3200, underexposed 4 stops in lightroom.
ISO 3200 underexposed (pulled back?)
ISO 200 underexposed in camera (not enough shutter)
Now that i have done these experiments, i revert back to my original belief, its better to over expose than to underexpose (unless ofcourse you are dealing with a scene with significant amount of differential in lighting, where its better to have more black than blown out whites)
remember that you cant "push" information that is not there
when you push ISO 800, if for any given pixel, you dont increase the noise, that means by definition you cant increase any of the light either, because there isnt any!