We’ve frequently talked about using polarizing filters to make more striking landscape photographs, but they are at least as important for making more vibrant portraits, and cutting your retouching time in half. Let me show you how it works, as well as some general tips.
What Does a Polarizer Do?
Polarizers reduce the visible affect of reflections–that’s it. The sky is full of water vapor and other particles which reflect sunlight, and most things that reflect sunlight appear white, right? The polarizer removes those reflections leaving behind the true blue sky. Leaves on trees and grass also reflect the sun, so it reveals their truer colors, too. Most buildings also reflect light, and the polarizer allows their rich colors to show. Overall, a polarizer will yield a more richly colored photograph every time.
Guess what? People’s skin also reflects sunlight.
Polarizing a portrait not only makes the sky, foliage, and buildings more rich and vibrant, it also removes much of the shininess on a person’s face. Oil on skin reflects light, making a shiny appearance. In the portrait below, my subject had just had makeup done (by Denise Christensen) so her shine was already minimal. But compare the left and right images and you’ll see that the polarizer removed all the remaining shine, leaving only the smooth skin tones Denise made with makeup. Click the image to view larger.
The sky is richer, the grass is greener, the building is more saturated–even the cliff in the background and her black shirt look better–but most importantly, her skin has no shine to it. That means that my image right out of camera is ready to go to with practically no retouching, and that’s a huge time savings, and it makes me look good in front of my subject and my client, and it shows Denise’s work at its best, too.
I use the B+W F-Pro circular polarizer*, which I bought in the 77mm diameter size, and I use it with step-up rings to fit my smaller diameter lenses (that way I only buy one expensive filter–step-up rings are cheap). It’s made of brass which means it never gets stuck on my lenses. I bought mine from Pictureline–I called and talked with a real photographer who helped me select exactly the right tool for my budget–love their service.
*All polarizers you buy in a store today are ‘circular’ polarizers. Circular refers to the type of polarization they provide, not their shape; I have a square circular polarizer–it’s a physics thing.
Notes on Exposing with a Polarizer
In the captions above you can see that these two captures were made with the exact same exposure settings in the camera. It’s noteworthy that the polarizer is attached to the lens for both pictures, but it wasn’t activated in the image on the left. Polarizers are dark, so your exposure with the polarizer removed is brighter. Also, as you rotate the polarizer to activate it, you remove all those shiny highlights, which fools your camera into thinking the picture is darker; if you use Aperture mode to shoot, you’ll see the shutter speed get slower as you rotate the polarizer. But don’t be fooled! The correct exposure is the same for both the polarized and unpolarized frames.
I strongly recommend you remove the polarizer when you’re not actively using it. It’s darker–one to two stops darker, which usually means a slower shutter speed. I’ve often had students leave the polarizer on all the time, but making a portrait indoors where it’s not needed means the shutter speed could go from 1/125th of a second without it to 1/30th of a second with it, and it’s hard to make a sharp picture at such slow speeds.
Polarizers Work at 90 Degrees
Point your index finger straight out, and stick your thumb straight out, like an “L” shape. Now, point at the sun with your finger and rotate you wrist: wherever your thumb points is the most polarized part of the sky and your filter will have the most affect in that arc (you’ll get the bluest skies). I don’t totally understand it, but polarization works at 90 degree angles. (Special thanks to Mr. Barbara for that finger-pointing tip–I don’t remember much from my high school photography classes, but that one stuck :) )
That’s why I chose the backdrop for the portrait above. The sun was just about directly to my left, which puts the sky behind my subject just about 90 degrees to the sun, which is why the polarizer has such a strong affect on the sky in that image. Also, she’s a city planner…so we wanted the city buildings in the background.
The image at the top is a horizontal portrait I made moments before the other two. When I rotated the camera to the vertical orientation, I depolarized the image (which is why I have the flubbed one above). If you rotate your camera, you have to re-adjust the filter orientation.
More on Polarizing…
Using a polarizer in your portraits will make them more vibrant, and save you time touching up shiny spots, and that makes it well worth the price of getting a good one. They’re like magic! I’ve read quite a bit on how they work, and I still don’t totally get it. There’s lots of math if you want to learn it… Or you could read these other excellent articles by Mark Morrow, Nicole Young, and myself.