At 23:52 6/7/01, Vaughn Bromfield wrote:
Tony
A lens hood doesn't stop flare. It merely shades the lens from off-axis
non-image-forming light. The "ideal" lens hood would exclude all light
except that from the subject: it'd be huge. All practical lens hoods are
much smaller, so they are compromised.
If the sun is in the frame, or very near the edge of the frame, no
practical lens hood will help. You are at the mercy of the lens's
quality of design, build and multi-coating, because flare control is
difficult and expensive. (Photographing into the sun is the "acid test"
that sort out the ordinary lenses from the Great, and where most third
party lenses -- especially zooms -- fail miserably. You *do* get what
you pay for, in tricky light situations.)
I always use a lens hood, if only for physical protection. I also shade
the lens with my left hand during exposure, checking the dof preview to
make sure it's not visible. Often the reduction in flare is dramatic and
can be easily seen in the viewfinder.
I'm siding with Vaughn in this one. While the Oly hoods help, they do not
come close to what is required to block out _everything_ except what's in
the field of view. For that you need a rectangular one with an aspect ratio
of 2:3 that's long enough to be a tunnel. There are aftermarket
rectangular bellows type hoods for just this purpose (expensive) and they
allow adjusting their length (the reason for the bellows).
I don't use them (bellows hoods). I do religiously use the Oly hoods; any
hood is better than no hood if it doesn't vignette (unless you want it
to). If the sun is in front of the film plane, but not in the field of
view, I look at the lens front to see if it is shining on it and then
provide additional shade if required. Flare effects, especially aperture
flare, is sometimes hard to see in the viewfinder but can be brutally
visible looking at the developed film afterward.
-- John
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