Sue Pearce wrote:
> I don't understand how details obscured by haze
>
The concept is pretty simple.
Suppose I shoot a nice, black and white Holstein cow with a long lens
through hazy air. The black part becomes a bluish dark gray and the
white part becomes a bluish light gray. The effect may even be so bad
that I can't really distinguish the markings at all.
However, in a digital/digitized image, as long as most all of the once
white part pixels are tonally higher than all of the other part, it's
relatively easy to restore the contrast and compensate for the blueish
cast.
In fact, if I shot a painting of a cow done only in pure white and
black, it can be completely restored as long as the tonal values of the
two parts are at least one step apart. Lower everything below that value
to black and everything else to white and you have recreated the subject.
In the real world, of course, it's not quite as straightforward. For one
thing, aside from haze, there is usually loss of detail from air
movement. And little in our typical images is pure black and white.
Nevertheless, it is often possible to recover a great deal of the
original color and contrast. If you have followed my adventures in
creating alternate versions of images posted here, you have seen many
examples. Much more can be recovered in the digital darkroom than
through use of a haze filter. The other application where a filter does
something post can't is UV filtering for high altitude shooting.
> , reflections, etc. can be recovered in post.
>
Generally can't be done for reflections. For me, the only times a
polarizer is needed are for "seeing through" reflections in water, glass
and such and for taming specular reflections.
As for recovering from "etc." effects, it depends. ;-)
A. Hazy Moose
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