why and when to use a PM polarizer?

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Polarizing
filters are a magical thing! With the advent of digital photography and
computerized post-processing, software is now able to recreate many of the
effects that creative filters were used for in the past. However, polarizers
are one of the few types of filters whose effects cannot be recreated in
post-processing. Polarizers change the light coming into the camera and can do
some pretty amazing things!

 

The
most common use of polarizing filters is to remove glare from water allowing
you not only to see below the surface of the water, but to enhance the overall
color of images containing water. But this is far from all that a polarizer can
do for you!

 

Purchasing
a polarizing filter:

The
first thing you want to make sure of is that you purchase a circular polarizer
(sometimes referred to as CPol) if you are just newly stepping into the world
of polarizers, as opposed to a linear polarizer. Linear polarizers will cause
your in-camera light meter to be unreliable and maybe even unusable. The good
news is that circular polarizers are easy to find!

 

As
with most things photography related, you get what you pay for. Polarizers
consist of more layers than a typical UV or color filter, and as a result, they
are more complicated to manufacture and therefore more expensive than other
types of filters. It is important that every layer be of a good quality,
otherwise the filter will degrade the quality of the final image. Expect to
spend a minimum of $100 on a good quality circular polarizer. (B+W and Heliopan
are great brands!)

 

As
with all filters, the size of filter that you buy is based on the filter thread
of the lens you are using. However, if you would like to be able to buy just
one polarizer and be able to use it on all your lenses, here’s a money-saving trick.
Buy your polarizer in the largest filter diameter of all your lenses (or even
bigger if lenses with larger filter threads are on your wish list). Then, buy
stepping rings so that you can attach the polarizer to your lenses with smaller
thread diameters.

 

I
have a 72mm polarizer, but my current lenses have 62mm and 52mm threads. I also
have a 72mm to 62mm stepping ring and a 62mm to 52mm stepping ring. I use
either one or both of the stepping rings depending on the lens that I am
attaching the filter to. Stepping rings cost under $20, so a couple of those
are far cheaper than buying a separate polarizer for each lens.

 

How
to use a polarizer:

Start
off, of course, by attaching the filter to your lens. While looking through the
viewfinder, rotate the outside edge of the PM
polarizer. You will see the colors and saturations change as you rotate
the filter. When you achieve the desired effect, shoot away! As you rotate the
filter through 360°, it will go all the way from minimum effect, to maximum
effect, and back to minimum affect TWICE! Or to put it another way, it only
takes a 90° rotation to go from minimum effect to maximum effect. Why does this
matter? Well, if you’re shooting in landscape orientation and you have rotated
your filter for the desired effect and then switch to portrait orientation
(rotating the camera 90° in the process), you’re going to completely chance the
polarization effect. Every time you change the orientation of you camera, you
have to re-adjust your filter.

 

Polarizers
are most effective when shooting at a 90° angle to the sun. So if the sun is
directly to your left or right, you are going to see the most dramatic
differences as you rotate the filter. If the sun is directly in front of you or
directly behind you, you may not see much difference at all.

 

When
to use a polarizer (and when not to use one):

If
you want to remove glare from water to take photos of what’s below the surface,
this is where a polarizer is really irreplaceable! Here is a photo taken both
with and without a polarizer. I promise, there really were dolphins under the
surface of the water in both photos, but the glare from the surface of the
water meant that without a polarizer I was never going to be able to photograph
them.

 

Polarizers
are also great at boosting the overall saturation of an image and can make
pretty blue skies even bluer, giving an image with more tonal contrast.

 

As
I mentioned above, polarizers are most effective when shooting at a 90° angle
to the sun. This is something that you want to be mindful of when shooting with
wide angle lenses. When using a 24mm lens on a full frame camera, you will have
an approximately 84° angle of view. This means that one edge of the frame could
have the full effect of polarization, while the opposite edge of the frame
could have next to nothing. This can result in some pretty crazy and
unappealing gradiations in the color of the sky.

 

Polarizers
are like putting sunglasses on your camera. Depending on your exact filter,
they can end up giving you 1-2 stops less light. If you are already shooting at
the low light limits of your camera, it may be better to forego the polarizing
benefits in exchange for the additional light you can get into your camera by
removing the polarizing filter.

 

And
one of my favorite little secrets…rainbows have polarized light in them! When
shooting a rainbow with a polarizing filter, it will make the colors more
vibrant resulting in an almost magical quality that will have you wanting to
search for the pot of gold!

 

If
you have never tried shooting with a polarizer before, I’d highly encourage you
to give it a try. It can bring a new level to the natural color and contrast of
outdoor photos, and it can open up a whole new world of possibilities when
taking photos that include water and glass by allowing you to take control of
the reflections that you are presented with.