The Polarized Porsche

Like barnacles on an old ship, filters tend to accumulate in an old photographer’s cabinet, and those filters are generally about as useful as barnacles, which is to say, not much. Sure, they all have a function—the blue, the red, the orange, the yellow, the green. But I don’t even remember the last time I used one of those, though I have them all and used them at one time or another. Truth is, beyond something more or less clear to protect the front of your expensive lens, if you shoot digital and are facile with something akin to Photoshop, you can get by nicely with only a single filter, a circular polarizer.

The polarizing filter has really good job security because nothing else does what it does, and even the most elaborate processing of a digital image after the fact can’t fully duplicate its effects. I’ll spare you the discussion of the nature of light waves, and how circular differs from linear polarization: interesting, but not necessary for the ideally polarized Porsche. It might also be noted that the more expensive circular polarizer is recommended only because it doesn’t confuse the focusing and metering systems in modern autofocus cameras as the linear ones might.

When you have to shoot in direct sunlight, a polarizing filter helps to reduce hot spots reflected from the paint. Note the signature intense blue sky.

LEONARD TURNER

Taking the time to replace your lens-protecting filter with a polar (avoid “stacking”—using multiple filters—as this may degrade the image) can produce the familiar super- dramatic blue sky effect, but there are two other potential benefits for shooting cars. The first of these is intensification of colors: in the right light, rotating the front element of your polar can make the car really “pop” without the color looking overly boosted. Chalk this up to reduced surface reflections from the paint, but don’t expect the same happy result from bare metal: you won’t get it. A glare of chrome will still wind up in your final shot, although sometimes moving the camera only a bit to get a different angle will help.

This shot tells the story of a team getting ready for a rally, but it could be much better.

LEONARD TURNER

With no manipulation other than adding polarization, the car’s color is much purer and more intense, and the windshield has disappeared to show what’s happening inside the car.

LEONARD TURNER

But glass is not metal, and here the polar is a tiger for reducing surface reflections. Showing what’s going on beyond the outside—the interior, the driver, the passenger—can be what moves a shot from the realm of average to great. Try it too for those shots when you are shooting through the windshield from inside the car. Watch out for clear plastic, though—internal stresses may produce some interesting but undesirable effects when polarized, and some safety glass can at times produce unwanted patterns. The good news is that you see the effects of polarization in your viewfinder and can alter the effect by rotating the front ring of your filter.

This shot is probably better without polarization. The shadows and reflections are an important part of the image. Choose your weapons for the battle at hand.

LEONARD TURNER

That degree of control is important, because not every car shot benefits from polarization. Reflections in the paint can be important in showing the lines of the car and may be a part of making your shot interesting and dynamic. And there are times when you want to avoid making the glass more or less invisible—maybe you don’t want the car interior to be prominent: you wouldn’t want to reveal that there’s no one in the car in a simulated action shot! Sometimes too the full polarized effect is simply not pleasing when considered with the other components of the shot. Look before you shoot, or take a variety of shots and evaluate them later.

Other than the minor hassles of attaching a filter and introducing one more control variable to manage, a downside of a polarizer is that it eats a certain amount of your light, typically about 1 or 2 f-stops. While a circular polarizer doesn’t create an exposure problem (compensation is made automatically by the camera), the decreased light in the viewfinder can be an issue for the photographer wearing sunglasses; if your sunglasses are themselves polarized, you may see little or nothing!

The loss of light can be a problem, too, when the ambient light is low and no tripod is at hand to allow a steady camera at a slow shutter speed. But the major curse of using a polar filter is that the effect is dependent on the angle of the light source, with the strongest effect coming from side lighting; in some light, there is no effect at all—look before you shoot.

Grumbles aside, though, polarizing your Porsche is still another very useful trick in your photographic bag, one that not enough people bother with. Anything that is both fun to play with and which gives your pictures an extra something that other shooters may not get is worth a little trouble and expense, and is not likely to become a barnacle in your filter collection.

I'm leonardt@pca.org. Let me know your thoughts.