Originally posted by mike_berger Are hoods really needed . . .
If you've ever driven an automobile with a
dusty or dirty windshield and with off-axis, incident sunlight (or bright lights at night) you have a pretty good idea why a hood is a good thing to use. It's impossible to describe the difference in lose of contrast without having identical comparison images in hand but it's there. It would be presumptuous to assume you'll always have pristine glass in the field and it's a real PITA to keep it that way.
I've since misplaced the links, but a few years ago there were some excellent web posts illustrating this point.
Here's one excellent example from this forum:
About Lens Hoods IMPORTANT!
It's easy enough to generate one's own empirical comparison data with available gear and personal scenarios. I've done that and IME the results favoring hoods are so compelling I found no reason to keep the test images for future reference.
Reluctance to use a hood is a fine way to ensure kit lens quality images from
star quality lenses.