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Every experienced photographer knows and fears lens flare. Most often, we associate it with those horribly distracting 'stars' of light we see through our viewfinder and in our images when shooting into the sun. But not everyone knows that lens flare doesn't only affect those shots—it is part of every image we capture. So knowing how to reduce its effect is a valuable tool in many shooting situations.
Lens flare doesn't only refer to the little reflections of the sun in your lens. It is a term for the light that all lenses—even the best ones—smear all over the sensor when photons don't go exactly where they are supposed to after bouncing around through all the optical elements. The amount of lens flare in an image is directly proportional to the total amount of light entering the lens. Of course, the better the lens optics and coatings, the lower the absolute effect.
We don't notice lens flare most of the time, because the total amount of light entering the lens is small enough and indirect enough that the only effect is a slight lowering of contrast, often looking like a haze over the image. It's easy to blame the sky for that, and gloss over the contribution of the lens itself. If the flare effect is large enough it will wash out the black levels in the image, due to the excessive amount of light hitting the sensor. For severe cases, a simple initial fix is to use the Levels command in Photoshop or Lightroom (or the Blacks slider in Camera Raw) to move the image's black point up to the darkest levels actually captured in the scene. Often you can quickly accomplish the same thing, and adjust the whites at the same time, by using Auto Level. While that adjustment makes a large difference in the overall look of the scene and will add back much of its native drama, elements of the scene still won't 'pop' the way they did when you looked at the scene with your eyes. That's where a custom filter comes in handy. My favorite tool for dealing with this situation is NIK's Pro Contrast filter from its Color Efex filter set. Unlike many other contrast tools, Pro Contrast can be set to be color-neutral—and subtle—enhancing just the distinctions between mid-tones obscured by the hazing effect of lens flare.
This image of the U Bein Bridge had the composition I wanted, and the sun was setting in a gorgeous sky, but of course, the lens flare was substantial. Pro Contrast helped deal with the issue in a heartbeat. I left its color cast correction slider at '0'—since the whole point of the image is the orange light—and moved the Contrast and Dynamic Contrast sliders to about 50%, where I thought they looked good without distracting from the image—and then I applied the filter. You can see the 'before' image on the left and the 'after' image on the right. It's a little subtle on the screen, but makes a big difference in the quality of the resulting prints.
What about Lens Hoods?
At this point you may be asking what all the fuss is about since, after all, you dutifully use a lens hood—a product specifically designed to reduce the effects of flare. Unfortunately, if you are shooting in a direction anywhere near the sun, most hoods will have little effect. In particular, the hoods on zoom lenses need to be short enough that they don't cause vignetting when the lens is at its shortest focal length, meaning that they block very little light in most of the lens's range. If the sun itself is the culprit, you can sometimes hold up a hat or card to shield the front of your lens from the most direct rays, but that isn't always practical, and in some cases the sun's glare from the the surrounding clouds and sky create a messy situation all around. In those cases, your only options are post-processing, or some clever use of HDR and image compositing. (I've been known to shoot a scene with the sun blocked out to get a nice rendering of the shadow detail, and then again without it blocked, to fill in the sky.) The two resulting images can be combined into a single image which doesn't have the flare effects throughout. Filters on your lens also add to the total flare effect, so consider shooting without one when you're looking into the sun—or at least make sure you're using a multi-coated version which will help keep flare to a minimum.
Sun 'Stars': Serious Lens Flare
If the light entering your lens is concentrated enough, either from the sun or another bright light source, the image will have visible artifacts. These are sometimes visible as long rays, as in this image of Angkor Wat at sunrise, or in bright areas which mimic the shape of your lens's aperture blades. Fortunately, these are common enough that nearly everyone recognizes them as the indicator of a bright sun or light. You can use that to your advantage by working to get them lined up in a pleasing way in the image frame, using them to help illustrate the conditions of the scene where you're shooting.
Time Your Shot to Avoid Flare
Often, avoiding lens flare is simply a matter of timing. If you can capture a sunrise early enough, like in this image of the sun rising through the statue of a bull on the top of the Bakong Temple, or late enough as the sun sets, then the sun can become a natural part of the scene. Of course, those images will still have high dynamic range, so they often require a minus exposure compensation adjustment to expose for the sky, which in turn makes the subject a silhouette. If you'd like to learn more about digital photography, or how to capture images like these, we encourage you to visit our site, Cardinal Photo, and its sister site, Nikon Digital, which are both full of tips and reviews, and forums where photographers compare notes and tips. Or you can follow us on Facebook or join us on one of our Photo Tours and Safaris for plenty of experience and instruction in the field—including our next trip to Southeast Asia including Cambodia and Myanmar in January 2013.
Disclaimer: The opinions expressed in this piece do not necessarily reflect the views of B&H Photo Video Pro Audio