Originally posted by Mountain Vision In flat lighting it can be not used.
i disagree with this to a point
light is light,
if you see something, light is bouncing off of it, and if that something is not at 90* or more to your lens, and it is not part of the image, it is unwanted light.
this is ofcourse much less noticed under weak or flat light, or noticed at all (unless you compare it), and even much less iimportant nowdays with the contrast sliders in our PP programs,
but still, personaly i use a hood at all times, unless you have a very wide andle lens and you are using flash, but ohh well.