Suitable filters for weather photography
Landscape photographers use many types of filters, some being
very expensive. Luckily, with weather photography you don't
need many kinds of filters. Often, only a polarizing filter
is sufficient. In fact, a polarizing filter is all I use for
my photography, except for photographing the sun, with which
I use a neutral density filter.
Filters such as warming filters or gradient filters are little
useful for weather photography. Since you don't need to see
detail in the foreground at all in weather photos, gradient
filters are not required.
One other type of filter that may be useful is a UV filter,
simply because it will protect the lens surface from being
damaged. But keep in mind that any filter will add extra
reflecting surfaces to the optical path through the lens and
There are two types of polarizing filter: linear and circular.
These filters work the same way in that they filter out light
of a certain polarization. A circular polarizing filter is
useful for SLR cameras that use a mirror when light metering.
A circular polarizing filter consists of a linear filter and
a circular polarizer after that, to make the light circularly
polarized and therefore its intensity won't change after
subsequent reflections. If in doubt which one to use, use a
circular polarizing filter.
Many cloud pictures will benefit spectacularly when
using a polarizing filter, which increases contrast with the blue sky. Left photo taken
without filter, right photo with filter.
The filter is rotatable, and it has a mark that indicates the
axis of polarization.
Polarizing filters are extremely useful if you want to
photograph the weather, since they will often add contrast to
the sky and clouds, the rainbow, and many halo phenomena.
Usually you use the filter for the blue sky, since the blue
sky is polarized. By blocking some of its polarized light
out, the sky is darkened, and the contrast between the sky and
an unpolarized cloud is enhanced.
The sky is maximally polarized 90o away from the sun. If you
use a polarizing filter in combination with a wide-angle lens, you will notice the brightness
changes across the frame.
Some remarks about polarizing filters:
- Since the polarization directions differ under all circumstances,
you will have to see every time how much to rotate the filter
on the lens to obtain optimal contrast.
- Care must be taken if you photograph with blue sky overhead at
high altitudes, because the sky can be almost 100% polarized and
can be made to look black on photos.
- If in an airplane, you cannot use a polarizing filter to
photograph the clouds and such, because the airplane windows are
birefringent (the amount of polarization depends on the
wavelength), and you will see many colors.
- Some types of glass also cause polarization due to stresses
in the glass. A typical example is the patchy structure you sometimes
see on car rear windshields if you look at an angle. Such glass in
combination with a polarizing filter also causes undesirable results.
The birefringence of airplane windows renders any kind of polarizing
Neutral density filters
These are only useful if you need to photograph something in the sky
very close to the sun, like a corona or iridescence. But most modern
cameras have fast shutter speeds such as 1/4000 second, and then
these filters are not required.
The only neutral density filter that is useful to have is an ND5
filter that transmits 0.001% of the incoming light (a fraction of
10-5). These filters are useful if you want to photograph
or observe the sun during the daytime, like a partial solar eclipse,
multi-sun exposure, or when photographing sunspots with a telescope.