an overexposed/whiter picture, too little light = underexposed/blacker picture should be
an overexposed/brighter/blown out, too little light = underexposed/darker picture
Also, ISO effects how sensitive to the light around. The higher the iso the more sensitive and faster the shutter speed. The lower the iso the less sensitive and the slower the shutter. Note, the higher iso causes the dark areas to become noisy.
I could go on for hours on photography and stuff because there's so much in it.
Great tut by the way.
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