Q: How does a digital camera take pictures?

A: Instead of capturing light on a piece of photo-sensitive film like a film camera, a digital camera reads light using an image sensor, typically a CCD or CMOS sensor, and stores the information to memory as a digital picture file. The more pixels a sensor uses to read light, the more detailed the photos are.

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Q: Are the settings on a digital camera hard to figure out? What if I just want to "point and shoot?"

A: Today's digital cameras offer many helpful features and settings, but even with the extra options (and buttons), they're still very easy to use. Both point-and-shoot cameras and more advanced SLR models come with goof-proof automatic settings — start with them, then try out the more sophisticated features as you get more comfortable taking photos.

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Q: What do all these "scene modes" do?

A: Digital cameras, especially point-and-shoot models, offer preset exposure settings designed to help you take better photos under a variety of shooting conditions. You'll see scene modes like Portrait, Landscape, Sunset, Fireworks, and Museum. When you want to take pictures in one of these situations, just select the appropriate scene mode, and let the camera automatically choose focus, shutter speed, aperture, white balance, and flash options to match. You'll find these presets helpful for taking great-looking shots in tricky photographic environments, without a lot of thought or effort.

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Q: Why do some cameras have an LCD screen and a viewfinder?

A: Generally, it's easiest to frame shots using your camera's LCD screen. Sometimes, though, glare from the sun makes it difficult to compose or review pictures on the screen. That's when having a traditional viewfinder is a great bonus. Also, when you frame shots with your viewfinder, you can steady the camera against your cheek, helping to prevent accidental camera shake and blurry pictures. Taking pictures using the viewfinder instead of the LCD screen also saves battery power.

While digital SLRs have an LCD screen for reviewing photos, you'll normally use the viewfinder to compose shots with this type of camera. However, a new trend has SLRs including live view LCD screens, on which you can frame pictures just like you would with a point-and-shoot camera.

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Q: What kind of memory does a digital camera use?

A: All of today's cameras accept flash memory cards, such as a Memory Stick, CompactFlash card, or SD (Secure Digital) card. Plus, some cameras also come with embedded flash memory that allows you to store a handful of high-resolution photos. The memory that a digital camera uses, whether built in or on a removable card, is reusable. That means you can transfer or delete the images on it, then use it again for picture storage.

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Q: I've taken a few digital photos using my new camera. What do I do now?

A: The most common next step is probably to transfer your pictures to your computer. Most digital cameras come with a USB cable for connection to a USB-capable PC or Mac — simply connect the camera and transfer the pics. (Another possibility for transferring photos to a computer is via a camera dock or a compatible memory card reader.) Once the photos are on your desktop, you can edit them, e-mail them, post them online, even print them out using your computer's printer. You can also print them using an Internet-based print service — the prints can be mailed to your home or you can pick them up at a store.

If you have a stand-alone digital photo printer that is compatible with your camera or your camera's form of memory, you may be able to print directly from the camera or the removable memory, without having to use a computer. Also, most photo labs will print directly from a CD or memory card.

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Q: While looking around at digital cameras, I've occasionally noticed two different pixel counts for the same camera. Why?

A: Some manufacturers publish two different pixel counts for each camera, and both numbers are correct. Here's the difference. One of those numbers is the actual pixel count — it's the number of pixels present on the CCD. The other number, which may be the same or slightly lower, is the effective pixel count. Effective pixel count is the number of pixels that are actually used when a picture is taken; some pixels on a CCD don't get used for picture information.

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Q: What's the difference between optical and digital zoom?

A: Optical zoom involves a zoom lens, just as it would on a traditional camera. A camera with an optical zoom of 3X can actually give you a picture that's three times closer than the basic, unzoomed image.

Digital zoom, on the other hand, is a digital technology that takes a real optical image, and "zooms" it by blowing up each pixel and using interpolation — essentially, adding fake blocks of color to fill in the gaps that result, based on what colors it thinks would have been in those spots. For the most part, digital zoom results in an instant decrease in an image's clarity and sharpness. Images rapidly become blocky and pixelated as you continue to zoom.

For that reason, if you're interested in sharp, crisp close-ups of faraway objects, always consider a digital camera's optical zoom spec, not the digital zoom spec.

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Q: What is image stabilization, and will I see a difference?

A: Many cameras feature image stabilization, which uses special sensors to detect camera shake and counteract its effects. The camera moves either the lens elements or the image sensor to compensate for tiny camera movements. Image stabilization is particularly good at retaining crisp edges in photos that would otherwise be prone to blur, such as long-distance zoom shots, or pictures taken in low light, where the camera's shutter speed slows down.

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Q: What kind of resolution do I need for sharp photos?

A: If you're just going to be posting photos on the Web, you don't need very high resolution — even 640 x 480 should provide nice, clear images.

If you want more detail, and may be printing out some photos in smaller sizes, anything from 1600 x 1200 to 2048 x 1536 should cover your needs — just remember that higher resolution makes for cleaner, crisper pictures, but it also causes the stored photo to take up more memory.

If you want to make very large prints — 8"x 10" and above — consider going with a camera that offers at least 3072 x 2048 resolution or higher. High resolution is also important if you're going to be cropping out a portion of a picture and printing the cropped section in a large size — if the photo is high-res to start with, you're less likely to see pixelation when you blow it up. (You can also check out our resolution chart to compare.) The good news? Digital cameras have come a long way in the last couple of years, and all of our digital cameras have high enough maximum resolution to provide clear, large-sized prints, as well as sharp Web photos.

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Q: In shopping for cameras, I noticed that sometimes a 6-megapixel camera costs more than an 8-megapixel camera. Why?

A: Although megapixels are one way to judge a camera's abilities, it's sometimes not quite as simple as "more are better." What is true is "bigger is better" — at least when it comes to sensor size. The sensor is the chip that actually reads the light coming into your camera, and both its pixel count and physical size affect your pictures. You see, not all sensors with the same resolution are actually the same size. For example, some 6-megapixel cameras use a very small sensor, while others (usually high-end cameras) use a much larger sensor. The larger the sensor is physically, the more detail it gathers, and the more lifelike the images it records.

Sensors are measured using an outdated system of fractions based on old TV tube measurement techniques, so the specs aren't that intuitive to compare. Some sizes you'll often see, from smallest to largest, are 1/2.7", 1/1.8", and 2/3". Sometimes, you can also compare CCD size using actual millimeters, and that's far easier.

So, if you're comparing a more expensive, high-end camera to a budget-friendly one boasting similar resolution but less sophisticated features, chances are the first one has a bigger and better sensor.

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Q: I've heard that digital cameras have some kind of lag time between when you push the shutter button and when the camera actually takes the picture. Is this true, and what can I do about it?

A: Many cameras do experience something called "shutter lag." In general, shutter lag is the result of an automatic camera trying to assess proper focus and exposure and take a shot, as quickly as possible. Sometimes, the lag is not, strictly speaking, "shutter" lag — instead, it's a delay that occurs when a digital camera stores a recorded image. Once people get familiar with a camera which lags a little, they have an easier time adjusting for lag.

There are also some cool tricks for getting around it. One is to choose a camera with manual exposure and focus controls, and avoid automatic mode whenever possible. Another option is to look for a "continuous shooting" or "continuous AF" mode on your camera and activate that whenever you want ultra-responsive photo capture. A third trick involves keeping the shutter button half-depressed when you're shooting in automatic. That way, the camera stays focused and doesn't have to pause to focus once you push the button. And if you think your problem is one of processing, be sure to look for a camera with a "burst mode," and use that for squeezing off rapid-fire shots; in "burst mode," cameras can store a limited number of photos much faster than during regular shooting.

Currently, there's no set standard to let manufacturers publish specs about camera speed — partly because it's affected by so many additional factors. Fortunately, today's cameras are a lot speedier than early digital cameras — and the more high-end the camera, the less lag it's likely to have. You may also want to consider a digital SLR camera. They have greater response time than most point-and-shoot cameras — an SLR responds instantaneously to a press of a shutter button. If you're extremely worried about potential lag issues, read up on real-life user reviews of the model in question. You'll quickly get a sense of whether it commonly lags, or whether it's on the speedy side.

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