Using polarizing filters in outdoor photography: darken blue skies, reduce non-metallic reflections, saturate colors and more.
The Many Uses of Polarizing Filters
Suppose
someone told you that they could sell you a single lens filter that
could darken blue skies, saturate colors, remove surface reflections
(including window reflections), intensify rainbows and reduce
haze--would you buy it? You bet you would. And a polarizing filter can
do all of those things for you and, at times, using one seems almost magical.
Polarizing filters (or simply "polarizers" as they are often referred to) are one of the most versatile and
important photo accessories that you can own and, even though I use one
less with digital cameras than I did with film cameras (I'll explain
why in a minute), I still use one regularly. Polarizing filters work
(there's a lot of physics going on here and you can find lots of info
online if you're curious) by blocking certain wavelengths of light from
entering the lens and allowing others. They are sold in a rotating
mount that screws to the front of your DSLR lenses and as you rotate
the filter, it blocks different wavelengths. Among the things that a
polarizing filter does superbly well:
Darken blue skies.
By blocking extraneous scattered light reflections in the atmosphere, polarizing filters darken blue skies--and because they are mounted in a rotating base, you can adjust the degree of sky darkening. I use polarizing filters less for
this than I used to because I can create the same sky-darkening in
editing and have somewhat more control. I also feel that polarizing
filters tend to over-darken skies with digital cameras if you're not
careful about exposure and the exact rotation position. Sky darkening
works best when the sun is to your right or your left (of shooting
position) and not at all when the sun is behind or in front of you. You
can see the effect in the viewfinder as you turn the filter and as you
alter your position to the light.
Saturate colors. Once again, because you're blocking surface reflections, as you rotate the filter the colors of things like leaves and grass or
people's clothing becomes more (or less) saturated. This is the main
thing that I used to use polarizing filters for, but again, I can
saturate colors more selectively in editing. Still, I will sometimes
use a polarizing filter with landscapes where I want to control the
color saturation at the time I'm shooting.
Eliminate reflections.
This is something you really can't do very easily in editing! But with a polarizing filter you can remove
reflections from any nonmetallic surfaces by rotating the filter.
If you're shooting a store-window display, for example, you can
penetrate the reflections to show what's behind the glass. This can
be a real life saver in a lot of situations, especially when you're
traveling and might shoot a lot of store windows or displays.
Reduce atmospheric haze.
Polarizing filters are substantially more efficient at reducing haze (not fog)
than so-called "UV" (ultra-violet) filters and they're essential in
landscape photography for that reason.
Intensify rainbows.
No joke! By reducing the atmospheric haze and by blocking certain
wavelengths of light you can strengthen the colors of a rainbow
substantially. And because you can see the effect in the viewfinder,
you can decide how much intensity you want (yeah, like anyone would
dial up less than maximum color with a rainbow).
Polarizing
filters are not inexpensive and you will probably spend between $40-100
on a good one. If you're using auto-focus lenses, be sure to buy a
"circular" filter, but check your lens or camera manual to be sure of
the type you need.
I used a circular polarizing filter on my Nikkor 18-70mm zoom lens to darken the sky in this shot of crabapple blossoms.
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An Ambitious Dogs Production In Association with Boo Boo & Mama Cat Films Please also visit my Photo Tip of the Day blog.
