by Brenda Tharp
The goal is to get a histogram that doesn’t run off either the right side or the left side of the graph. A bell curve is the “perfect” histogram, but when was the last time you saw one of those on your LCD? In the real world, most histograms won’t look like that. That’s okay, as it usually means that you have contrast in your scene, which is generally better than lack of contrast. Just try to keep the range of exposure within the graph when possible and not have it spike on either side.
This histogram shows that we have a scene with good tonal range, except for the spike on the right side. With it running up the side of the histogram, in simple terms, we have most likely lost the detail in those highlights. If it was just touching but not spiking up the right side, the exposure would have worked out pretty well.
DEATH VALLEY NATIONAL PARK, CALIFORNIA. The low angle of morning light skimmed across the surface of this dune, creating a wonderful light/shadow relationship, and bringing out the texture at the same time. 70–200mm lens at 80mm, f/ 20 at 1/5 sec.
metering in a nutshell
Ideally, we should all be able to look at a scene and know what shutter speed and aperture combinations will give us the correct exposure. The more you can see a scene in certain light and say, “f/11 at 1/125,” the faster you can respond to capturing that scene. Photographers who can do this know how to “read” light from learning how the camera reads light. But many photographers today simply rely on the meter in the camera. While today’s camera meters are very accurate, there are conditions under which the camera’s meter reading may still be incorrect. Since all light meters in cameras are calibrated to read 18 percent reflectance of light from the scene—the equivalent of middle-tone, or neutral gray—both darker than middle-tone and lighter than middle-tone scenes are rendered as middle-tone. The moral here is that if you don’t want medium-gray snow or medium-gray black bears, you’ll need to compensate by overexposing or underexposing from that meter reading. In general terms, you’ll add light to light scenes and subtract light from dark scenes by compensating from the meter reading.
Of course, all of this is relative to the effect you want. Sometimes, a slightly underexposed image of a foggy scene evokes a certain somber mood that you might want, and a slightly overexposed scene can render a pastel effect. So it’s not always the technically correct exposure but rather the creative exposure that you want, as long as you’re not overexposing or underexposing large important areas of the scene too much.
On a scene that is stationary and repeatable, you can make adjustments and take another picture. But you can’t do this with events or where fleeting moments are occurring, so it’s important to understand how to get a good overall exposure on the first try, by knowing how to meter accurately. For a complete understanding of exposure, I recommend Bryan Peterson’s Understanding Exposure, 3rd Edition (Amphoto Books).
BACKLIT ASPEN TREES, BISHOP, CALIFORNIA. This was a tricky lighting situation, as the trees were in sun but the wall behind them was not. The leaves on the aspen were too small to spot-meter on easily, so I used evaluative metering. But because the amount of light and dark in my viewfinder was fairly equal in terms of overall proportion, I only had to underexpose by-0.3 to get a good exposure. 70–200mm lens at 200mm with 1.4x, f/ 16 at 1/40 sec.
THE COLOR OF LIGHT
TUSCANY, ITALY. Mornings often bring mist to the valleys in central Tuscany. On this particular morning we found a special scene. The color of the light was a great mix of cool and warm hues in that predawn hour. Moments like this are the reason I get up very early and get out there with my camera. 70–200mm lens at 165mm, f/16 at 2 seconds.
You don’t need to be a scientist, but knowing a few basics about the color temperature of natural light can help you make better outdoor photographs.
All natural light has a certain color that results from the way light rays travel through the atmosphere. Full midday light (white light) is about 5,500 degrees on the Kelvin scale, the standard for measuring the color temperature of light. By comparison, the color of sunrise will measure between 2,900 and 3,400 degrees Kelvin, and twilight will measure about 10,000 to 12,000. The lower the number, the warmer and redder the light; the higher the number, the cooler and bluer the light. Warm light is easy to see in the hues of a good sunrise or a glowing campfire. Cool light is easy to see in the deep blue of twilight. It’s the many variations between these extremes that are most difficult for the human eye to discern, because the brain corrects for color shifts, just like Auto White Balance does on a digital camera.
MISTY DAWN, MAINE. This is a favorite lake of mine near Camden, Maine. I loved how the blue light of dusk added a feeling of tranquility to the misty scene. 70–200mm lens at 78mm, f/ 13 at 1/5 sec.
BRISTLECONE PINE AT SUNSET, WHITE MOUNTAINS, CALIFORNIA. I knew a spot where I could get the last rays of the sunset striking the bristlecone pine trees. The reddish-orange light created a great color contrast of the tree against a cobalt blue sky. 24–105mm lens at 35mm, f/ 16 at 1/13 sec.
Why is it so important to learn about the color of light, when a digital camera can automatically white balance? In some cases, the actual color of the light may be making the picture more interesting, and if you let the camera take over color control, you might be losing the effect. Auto White Balance (AWB) neutralizes the color of the light it reads based on daylight parameters built into the camera, so if the light is “cool,” it will warm it up some, and if it’s “warm,” it will cool it down some. If the coolness of a foggy morning is what you want to show, AWB may ruin the effect by warming up that cool light too much. By learning to recognize the color of the light in a situation, you can make creative decisions in the field that will improve your picture. You can also use that awareness later when you process the file to get the color of the overall light to be what you remembered.
The color of light affects the color of objects in your photograph. The cool blue light of an overcast day will drain the rich hues of yellows, oranges, and reds of autumn leaves, so your forest scene may end up looking dull. A quick white balance change to Cloudy will help that. There are times when the color of the light is a strong warm hue, at sunrise or sunset, and yet the effect on your scene may not be so wonderful. The orange light of sunrise will make a field of blue flowers look “muddy.” You’re mixing colors like paint in this instance, and white balance settings can’t really improve the flowers without changing the color of the light in the whole scene and potentially negating the warmth of your sunrise. So if you want a field of blue lupine to look accurate for the flowers, you’ll need to wait until the color of the light is a little more neutral, usually about 45 to 60 minutes after sunrise.
GIANT GEYSER, YELLOWSTONE NATIONAL PARK, WYOMING. For these two pictures, I simply changed my white balance setting. The sunset had gone flat, and twilight was not yet rich enough, but with the camera set on Tungsten, I was able to create a nice twilight effect by adding to the blue light already in the scene. 24–105mm lens at 27mm, f/14 at 1/2 sec. First frame: White Balance set to Tungsten. Second frame: White Balance set to Daylight.
setting your white balance
Your camera offers a variety of white balance settings to correct the color temperature of light. How do you decide which to use? First, it’s important to note the difference between photographing in RAW or JPEG mode. If in JPEG, changes made in-camera are incorporated into the camera’s processing of that JPEG, and the resulting file has the color correction embedded in it. You won’t need to correct it later in the computer, thus protecting the JPEG from potential degradation with additional manipulation. If in RAW mode, the setting is somewhat irrelevant, as you can safely modify it later when processing the file. However, for new photographers, I still suggest setting it in-camera, as this teaches you to pay attention to the color of the light, part of mastering the craft of photography.
As to which setting to use, it’s pretty straightforward. When you’re under cloudy conditions, set the white balance to Cloudy;
when in shade, set it to Shade, and so on. You could also choose to use Auto White Balance (AWB), and 95 percent of the time it will be fine, but if you learn to see the color of light, you’ll be more aware of when AWB may not be the best choice. I use Daylight, which applies no color correction, and modify it later in the computer.
Understanding how white balance settings affect your camera’s response to different color temperatures will give you one more creative tool. With a little practice, you can train your eye to see subtle variations of color temperature. The key is to remember what conditions or times of day produce a particular color of light. Sunrise and early mornings are typically warmer, midday light is fairly white or neutral, and afternoons and sunsets are warm again. Cloudy, rainy days tend to have a cool, bluish cast to them. Open shade has a deeper blue cast. High altitudes (above 4,000 feet) are cooler than you think, even at sunset.
MODIFYING THE LIGHT WITH FILTERS
Because color correcting the light can be done with digital camera settings, I don’t have to carry all the filters I used to have in my bag. I like that! It leaves more room for other accessories. But there are still some filters that digital photographers need to carry to modify the light in a scene.
POLARIZING FILTERS
The most essential filter for me now is a polarizing filter. Both digital and film users need polarizing filters. These wonderful filters reduce the glare from the atmosphere on sunny days to deepen blue skies and create strong contrast between the sky and clouds. They also reduce glare from wet or shiny surfaces, producing more saturated colors. Polarizing filters work best when used at a 90-degree angle to the light source, typically the sun. Light waves normally vibrate in all directions. Polarizing filters eliminate the scattered light and only allow the light that vibrates along one plane to reach the camera. This reduces glare and increases contrast. If you’re working with morning or afternoon light coming from the side, your scene will have maximum polarization. But with wide-angle lenses, your sky will be polarized unevenly, an effect that many don’t like in landscapes.
Polarizing filters are also great in the forest, as they minimize reflective glare from wet leaves, rocks, and mosses. By reducing surface glare, they allow you to see into tide pools and shallow ponds. I use my polarizer more under these circumstances than I do on a sunny day!
LILY PADS, MAINE. These pictures show how useful a polarizing filter can be in situations other than skies. The filter removed the surface glare off both the water and the waxy surface of the lily pads. The comparison is strong evidence for why you need to always consider whether a polarizer would help improve your picture. 100–400mm lens at 280mm, f/ 16. First frame: 1/10 sec. for polarized. Second frame: 1/20 for non-polarized.
GRADUATED NEUTRAL DENSITY FILTERS
Unless you know how to use the gradient tool well in Photoshop, or how to blend different exposures together with various computer techniques, you’ll need these filters to balance the light in many situations. Using a filter, you can see the effect immediately, and that means less time spent at the computer to fix the picture later. And not everything is easily fixed by the editing software.
Graduated neutral density (ND) filters allow you to compress the range of light in a situation that is normally too extreme for the camera to record. You’ll most often use these filters when photographing landscapes or seascapes in which the sky is too bright when you get a good exposure for the land or sea.
They come in various densities that are equivalent to f-stops, such as a 2-stop (.6 ND). If you are just learning to use graduated ND filters, a 3-stop (.9 ND) is a good choice, as RAW files can usually manage a 2-stop difference with little problem. The 4 × 6–inch rectangular filters that fit in a holder are the best style, as they allow you room to shift the line of gradation in the composition when you put your horizon higher or lower in the frame.
The easiest and fastest way to use a graduated ND filter is to match the gradation line on the filter with the “line” between the light and dark areas of your scene. With soft-step filters, though, it’s not always easy to see the filter’s line, even when the lens is stopped down. Here’s a tip to make it easier: Fold a 4 × 6–inch piece of paper in half so it’s 4 × 3 inches. Place it over the top edge of the filter and place the filter in the filter holder on the lens. When you look through the viewfinder, you will very easily see where the line is on the filter as you adjust it up or down. Soft-step graduated filters, which have a feathered line, are more forgiving, making placement not as critical as with hard-step filters.
VIRGIN RIVER, ZION NATIONAL PARK, UTAH. Using a Gold-N-Blue polarizing filter, I was able to enhance the colors of this scene. To achieve a natural effect using this filter with digital photography, I set my temperature slider to 3,240 and my tint to -48 in the RAW processing. 24–105mm lens at 32mm, f/ 11 at 1/3 sec. First frame: Gold-N-Blue filter. Second frame: No filter.
OTHER FILTERS AND ACCESSORIES
I use various other filters to enhance color or add special effects. One particular filter that is invaluable to me is Singh-Ray’s Variable ND filter, which, when rotated, adds from 2 to 8 stops of density. It’s great for slowing the shutter speed down in bright situations. I’ve used it for coastal scenes when I want the wave action to be very soft and blurred, as well as for midmorning images of white-water rafting and other action events, to create artistic interpretations of the motion.
GREAT SMOKY MOUNTAINS NATIONAL PARK, TENNESSEE. Using a 3-stop graduated filter, I was able to capture the rich hues of the sky while not totally silhouetting the ridgelines. I placed the filter over the sky portion and used evaluative metering to make the exposure. 70–200mm lens at 280mm with 2x teleconverter, f/ 10 at 2 seconds.
Outdoor photographers don’t have total control over the quality of the light, but you can use accessories to modify it. If you want to do macro photography and can’t wait for an overcast day, make your own diffuse light by placing translucent fabric between the sun and the subject. Diffusers are available as ready-made discs that fold up with a twist of the wrist. I never leave home without mine.
What if you have strong sunlight and don’t want to alter the quality of the light yet need to balance the contrast? You have two options: You can use reflectors to bounce light in to the shadows, to compress the range of light, or you can use your flash in “fill” mode. In outdoor photography, the key to successful “fill” using a reflector or flash is to make it appear as natural as possible. Reflectors are easier, because you see the fill light with your eyes before making the picture. With flash, you have to review the LCD. Yet they both serve a purpose with outdoor photographers.
TWILIGHT, SONOMA COAST, CALIFORNIA. A variable ND filter allowed me to create a moody, ethereal effect in this scene. Varying the neutral density filter by rotating it, I had a range of choices to slow my shutter speed down to get just the effect I wanted. 80–200mm lens at 200mm, f/ 16 at 1/15 sec.
Your fill light should always be less than the main light source—for example, the sun. Silver and gold reflectors are pretty intense, creating a strong, somewhat harsh light that may be too much for nature scenes. White reflectors are less intense and neutral in color. But there are combinations called “soft gold” for example, that reduce the intensity a bit.
With flash, you’ll need to control the quantity of light. For easiest and best results, you’ll need a programmable flash that talks with your camera. You’ll simply set your flash compensation to the negative side of the scale, something like −1 or −1 2/3, and the camera and flash “talk” to determine the exposure. To know where to start, do a quick test in full sun, using all the minus settings for flash compensation, and choose what looks natural to you. That setting will then be a starting point for future pictures in sunlight needing fill-flash, although you might make a slight adjustment for the particular situation.
The quality of the light from flash is similar to that of the sun—i.e., specular, creating hard edges, harsh light, and deep shad
ows (when used in full flash mode). Compensating with less light doesn’t change the quality. You’ll need to diffuse the light from the flash, because if any shadow edges do show in your picture, it will appear unnatural. There are a variety of accessories to help you do that. My favorite for its effect, price, and size is Sto-Fen’s Omni Bounce. Digital has made it easy to practice using your flash and review the results. If you learn how to set your flash correctly for natural-looking fill light, you can create very pleasing results.
All of these are great tools to help modify or control the light, once you have learned the characteristics of natural light. The more practice you get in the field, the more you’ll develop your ability to see light and to previsualize the scene or subject under different lighting conditions. Learn how to recognize the best light for the situation, and you can use the magic of light to enhance your photographs.
BIGTOOTH MAPLE LEAF IN WASH, ZION NATIONAL PARK, UTAH. I diffused this scene with a translucent disc. When I put the disc up close to the subject, the light got stronger, yet remained diffuse, creating a soft directional glow to the light. 100mm macro lens, f/ 16 at 1 second.