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One of the biggest challenges in photography lies in capturing optimal exposures. Lighting conditions, subject matter, contrast levels: they are all factors in determining appropriate camera settings. In most situations, you can rely on the built-in reflective meter of the camera when shooting in all of the various exposure modes (P/A/S/M) to get good exposures. However, there are some instances where the reflective meter may not give you an accurate reading, particularly if your subject matter is either very light or very dark in tone.
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This lesson demonstrates, with the help of an Olympus E-1 digital camera, how you can use the various playback display modes to expose white subject matter at its brightest without risking overexposure.
(Most images can be clicked for an enlarged view.) |
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(Click on any image below for an enlarged view.) |
Topics Covered:
- The limitations of reflective metering
- Securing optimal exposure settings through playback modes
- Using the Shooting Information Display
- How to effectively read a Histogram
- Using the Highlight Display
- Comparing exposures
Equipment Used:
You can click on the blue links below for more info.
Camera/Media
- Olympus E-1
- Olympus ZUIKO DIGITAL 14-54mm F2.8-3.5 Lens
- 512MB CompactFlash card
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The reflective light meter in your camera measures the light that bounces off your subject matter, compares its value against that of middle gray, and then determines the appropriate exposure settings based on the difference. As you might imagine, reflective metering works great if your subject matter is neutral in tone, but what if your subject matter is white, like the horses shown above? You don't want to rely solely on the reflective meter's readings, particularly if it is set to Spot, because it will render your white horses as middle gray. To learn more, check out the lesson entitled, "How To Use The Spot Metering Mode". You could try to spot meter off of something else that appears to be more neutrally toned, like grass, but if its tone is too dark, your white horses may become overexposed.
As you can see, there are certain situations where reflective metering alone can be somewhat risky, particularly if you are on location and cannot download your images to a computer for closer inspection. However, there is a very effective playback method that ensures that none of the white areas of your images will become overexposed. And that's something that even a Polaroid cannot provide.
To demonstrate, we decided to take some shots of these white horses in a field with an Olympus E-1 digital camera. Before shooting, we made some adjustments to the camera. We set the Exposure Mode to Manual, set the Metering Mode to ESP, set the Focusing Mode to AF, set the ISO to its lowest setting (100), set the Resolution to TIFF, and set the White Balance to Daylight to match the color temperature of the sun (5500 K).
We then set the aperture to f/3.5 and used the reflective meter reading to determine the proper exposure. According to the light meter, our optimal shutter speed should have been 1/640th of a second. So, we set the shutter speed to 1/640th of a second, took a shot and pressed the green Playback button to review the result (figures 1 & 2). |
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REVIEWING IMAGE INFORMATION IN PLAYBACK
As you may have experienced, viewing images on your LCD can be subjective to say the least. Have you ever reviewed an image on your LCD, thought it was good, only to find later on your computer monitor that it was either too light or too dark? It's a common problem. Here's what you can do when you're riding the edge of light-toned subject matter.
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SHOOTING INFORMATION DISPLAY
With the image displayed in Playback mode, press the Info button once and you will see the Record Mode the image was shot in (TIFF, SHQ, HQ, etc.) Then press and hold the Info button down and turn the Sub dial until you see your image in the upper right corner of the LCD with accompanying white text on a black background. |
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This is Shooting Information display, one of three Detailed Information displays. Here, you can quickly review specific information about the image, including the exposure mode, the metering mode, the ISO setting, the color space, the lens setting, the aperture and shutter speed, the White Balance setting, exposure compensation, etc. (figure 3). |
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 Figure 3 |
While this information is helpful in reviewing your camera settings for a given image, it doesn't really tell you much about the exposure properties of that image. This is where the next two displays can be of use.
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HISTOGRAM DISPLAY
With the Info button still pressed down, turn the Sub dial until you see a Histogram displayed on top of your image. The Histogram basically tells you how all of the pixels in your image are arranged from dark to light. So, when you look at this particular image, you'll notice that there are pixels (represented in the white areas) that run across the tonal gamut, from very dark to very light, and that there are three major areas of tonal ranges: the blacks, the light grays and the whites. Each Histogram is unique to the image you are viewing, and will vary depending on the tonal range of the image.
When you see spikes on either end of the Histogram, it basically tells you that you have a high-contrast image and that you should watch out for over-exposing and/or underexposing elements of your shot. At the far right side of the Histogram, you can see that we are indeed in danger of overexposing sections of the image (figures 4 & 5). |
HIGHLIGHT DISPLAY
This final display mode is probably the most practical one to use, as it will clearly alert you to any areas of your image that are overexposed. With the Info button still pressed, turn the Sub dial until you see nothing but the Record Mode the image was shot in (TIFF, SHQ, HQ, etc.) If there are areas in the image that are overexposed, they will flash on and off in black. Notice in our example here, there is a significant amount of overexposure in these horses (figures 6 & 7).
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As you can see, this is one of those features that really saves the day. Had this been the only shot we took, we would have been disappointed later on in front of the computer with the lack of detail in the overexposed areas. But because we were able to see the flashing black sections in the LCD, we knew we had to take another exposure at a faster shutter speed: 1/1000th of a second. Afterward, we pressed the green Playback button for review (figure 8). |
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 Figure 8 |
Once this result was in Playback mode, we pressed the Info button again to pull up the Highlight Display. While we still had a few areas that were still too bright, our exposure was much closer to being where it needed to be (figures 9 & 10). |
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Finally, we made one last change to the shutter speed (1/2000th of a second) and took a our last shot. When we reviewed the result in Highlight display mode, there were no areas that were flashing, and we knew we had the brightest exposure of the horses while still maintaining detail in every area (figures 11 & 12). |
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Here you can see the results side by side (figure 13). |
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Remember to take a test shot or two and review them in the Highlight Display mode when you are shooting light-toned subject matter so that you can be confident of your exposure settings. Then, when you find yourself tracking zebras in the grasslands of Southern Africa like we did here (oh, alright, it was only the local zoo), you'll be able to come away with images from which you can make beautifully detailed prints (figure 14).
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 Figure 14 |
Equipment Used:
You can click on the blue links below for more info.
Camera/Media
- Olympus E-1
- Olympus ZUIKO DIGITAL 14-54mm F2.8-3.5 Lens
- 512MB CompactFlash card
Recommended Links
- To learn more about Photoflex equipment, go to www.photoflex.com
- For more detailed digital photography lessons, visit
www.webphotoschool.com
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