My eleven-year-old daughter told me a joke recently: A skeleton walks into a bar. It goes up to the bartender and says, "Gimme a beer ... and a mop."
What I like about that joke is the fact that the skeleton knew that, given its physical limitations, it was going to have to make some compromises in its quest for something to drink. And that's a lot like the way we take pictures with a digital camera--everything is a compromise. If we want to capture a bright blue sky, for instance, odds are good that the exposure elsewhere in the picture will be less than perfect. That's why many digital cameras have a feature called
The exposure lock works pretty much the way it sounds: When activated, it locks the camera's exposure settings so you can compose the picture any way you like and press the shutter release at your leisure. So if you want your landscape photo to have a perfectly blue sky, lock the exposure in the heavens, then compose and snap your picture.
But not all cameras include exposure lock. And of those that do, there's no standard way to activate it. Check your camera's user guide for details. The most common exposure lock system is activated by a button on the top or back of the camera, usually right under the spot where your right thumb would rest. The moment that you depress the button, the camera measures the available light and sets the exposure. And as long as you hold the button down, the exposure won't change. That's just an exposure lock--the focus isn't locked, of course, until you actually press the shutter release.
I've also seen cameras that lock the exposure not with a separate button, but by depressing the shutter release partway. With this sort of camera, you aim at the point in the picture you want to emphasize with perfect exposure and apply slight pressure to the shutter button. After a moment, the focus and exposure levels both lock, and you can then recompose the shot to taste. Press down the rest of the way to take the picture and remove the lock.
Whichever method you need to use with your camera, keep in mind that while this is a great way to make sure that a specific part of the scene is properly exposed, other parts of the image may suffer--especially if the lighting is radically different throughout the image. Consider the sky example, for instance. Ordinarily, digital cameras tend to overexpose the sky because they're trying to retain the detail in the darker ground elements of a picture. The result is that your sky loses color: It's bleached white by overexposure.
To retain the blue sky, point the camera up at it and lock the exposure, then recompose the shot to include the ground-level details. The camera's metering system "shuts down" to a small aperture and high shutter speed to accommodate all the bright light streaming in from the sky. So while the sky comes out looking great, with rich, attractive color, the darker ground will end up being underexposed. Is that okay? It's really up to you--there's no such thing as a proper exposure in photography.
Exactly the opposite happens in the shadows. Usually, digital cameras render shadows as deep, detail-less black blotches, because there isn't enough light to see what's really there. To fix this, point the camera into the shadows and lock the exposure. When you recompose the shot to include the picture's much wider exposure latitude, the brighter bits will be overexposed because the camera is using a slower shutter speed and a larger aperture to pull more detail out of the shadows.
A lot of the time, you may not need to use the exposure lock at all. The exposure meter averages the light throughout the picture pretty well, giving you a perfectly acceptable shot most of the time. For more info about exposure meters, read "Master Exposure Metering Modes."
But there are occasions when the lighting is simply too tricky: There's far too much contrast in the scene for the camera to figure out the exposure on its own. It's times like that when you need to step in, decide which aspects of the scene are most important to you, and rely on the exposure lock button to capture the scene you see in your mind's eye. Stay tuned for next week's column, in which I'll reveal a technique for getting perfect exposure even in very high contrast situations.
Have you ever fine-tuned the brightness and color of a picture on your computer display only to discover that, when printed, it looked totally different than what you expected? That's the risk you run when you use a monitor that's not properly calibrated.
The fact is that every monitor is a bit different. Yours doesn't really know how to display your digital images. So when you adjust a picture so that it looks great on screen, you may be wreaking havoc with its printed appearance.
ColorVision's $169 Spyder is a combination of software and hardware you can use to set your monitor so that it shows you your digital images just as they'll look in print. It includes a USB colorimeter that fixes your monitor automatically, eliminating the need to fiddle with color settings manually.
Using the Spyder is a snap. The software starts by walking you through basic calibration steps, like adjusting the brightness, contrast, and color temperature of the display.
The real magic happens when you snap the Spyder hardware onto the front of the screen. (It connects to both LCD and CRT monitors). A totally automated calibration system performs a battery of tests and adjusts the display. When it's done, you save your monitor's color profile in a file that you can use in your favorite image editing program. After you're done, put the Spyder back in its box for a few months. You'll want to recalibrate your display a few times a year, or whenever you notice the color starting to drift.
The Spyder is impressive. When I tried it, the entire calibration process took about 10 minutes. The difference was dramatic: Previously, my monitor was too bright and had too much blue; now, it's spot on.
Do you absolutely need a calibration tool like the Spyder? Probably not. Most people never make any monitor adjustments at all and live full and happy lives. But if you're a perfectionist hounded by the desire to match what you see on the screen with what comes out of your printer, you owe it to yourself to check out Spyder.
Recently, you wrote about failing memory cards. I have one more caution: do-it-yourself digital photo printers in department stores. I had a card loaded with about a dozen pictures and was trying to make 4-by-6-inch prints. For some reason, the computer locked up. The clerk who came to assist immediately removed the card without trying to reset the computer. I objected, but she insisted that she does this all the time. When I got home and tried to access the card, my computer would not read it.
--Silvio Cutuli, Wilmington, Virginia
Excellent advice, Silvio! And remember that the problem you mention can happen even if you're not at a department store. It's too bad you lost your card, but it's important to remember that a memory card can be killed in a heartbeat if you remove it while it's being accessed--from a memory card reader or the camera itself. That's why you should always turn your camera off before you insert or remove a card, and be sure the data light is off on any memory card reader before you yank the card.
Get published, get famous! Each week, we select our favorite reader-submitted photo based on creativity, originality and technique. Every month, the best of the weekly winners gets a prize valued at between $15 and $50.
Here's how to enter: Send us your photograph in JPEG format, at a resolution no higher than 640 by 480 pixels. Entries at higher resolutions will be immediately disqualified. If necessary, use an image editing program to reduce the file size of your image before e-mailing it to us. Include the title of your photo along with a short description and how you photographed it. Don't forget to send your name, e-mail address, and postal address. Before entering, please read the full description of the contest rules and regulations.
Rick took this week's Hot Pic of the Week with his Olympus C-750 from his backyard and converted the image to black and white on the PC in an image editing program. The resulting picture captures a certain drama that's difficult to achieve in color.
Dave Johnson
