BUYING GUIDE.
What kind of digital camera you choose will depend on how you plan to use the images you take, as well as the degree of flexibility you desire. Point-and-shoot models may cost less, but if you find them too limiting, it's worthwhile to pay more for manually adjustable models.Key Questions:
* What are you going to do with your pictures?
* What's the camera's optimum resolution?
* How expert a photographer are you?
* Does size matter?
* Does it come with rechargeable batteries?
Resolution evolution
The biggest question when buying a digital camera is what are you going to do with the pictures? If you plan to use them only electronically — posting them on a Web site, e-mailing them, or making slide shows for your PC or TV screen — then you need only a low- or mid-level model. If you plan on printing out your pictures, however, or if you need very high-quality, data-rich images, you want at least a 2 million pixel-plus (2 megapixel) model. (A million pixels equal 1 megapixel.)
What do these numbers mean? Is bigger necessarily better when you're shopping for a camera? The first thing to get straight is that camera resolutions are not expressed in the same terms as a scanner's or a printer's resolution. A scanner's resolution, for example, is given in pixels per linear inch (ppi). If a 600 ppi scanner has a scanning head 8" wide, the actual horizontal resolution is 4800 pixels.
Because digital camera image resolution is determined by the total pixel count, not pixels per inch, it's analogous to computer monitor resolution — a 13" VGA monitor and a 17" VGA monitor display the same number of pixels. In fact, camera manufacturers use the conventional terminology for monitors: "VGA" has 640 x 480 pixels (307,200 total pixels), "SGA" has 800 x 600 pixels (480,000 total), and "XGA" has 1024 x 768 pixels (786,432 total).
Obviously, 1 megapixel and 2 megapixel models offer resolution in excess of what's available with computer monitors. In fact, most 2 megapixel models contain more than 2 million pixels. Bear in mind that some stated resolution figures aren't entirely accurate. Many cameras tout a high resolution, but that optimum quality is often "extrapolated" — that is, achieved through software rather than by the camera's optics. Check to make sure that the stated resolution is achieved by the camera itself.
Display vs. print
Still, you should get the highest resolution you can afford, right? Not necessarily. To reiterate, if you're going to display a picture on a Web page rather than make printouts, you'll probably want to reduce the image to a size that will fit in a typical browser window (horizontal scroll bars are tres tacky on an on-screen image). You might want to further reduce the file size for quick downloading by saving it at a higher JPEG compression factor.
On the other hand, maybe you're an aspiring graphic artist who plans to subject your digital pictures to the more advanced image manipulation techniques offered by Adobe PhotoShop. The more information available in the original the better the potential results. Accordingly, a megapixel or higher camera might be worth the investment. (Bear in mind that we're discussing consumer models here. Professional digital cameras — some with 6 million-pixel CCDs — can be pricey.)
Extra pixels are also critical if you're going to print your images, whether in a family newsletter or a brochure for a small business. The higher the resolution, the larger the picture that can be printed without losing sharpness.
Paging Mr. Avedon, Mr. Brady, Ms. Bourke-White
Choosing a digital camera is much like choosing a film camera. Just like their film counterparts, digital cameras range from simple point-and-shoot models to elaborate SLR-styled (single lens reflex) models that sport substantial zoom lenses, macro capability and extensive manual settings. As with resolution, there's no right or wrong answer to the question of which is better.
Consider your own experience with traditional film cameras. Do you prefer the "Instamatic" ease of fixed-focus, one-button models? Or are you an experienced photographer who likes the greater flexibility offered by SLR cameras?
Look before you shoot
Above the entry-level range, most digital cameras feature optical zoom lenses, albeit not very powerful ones (it's rare to find much more than a 10x zoom). Higher-end cameras may allow you to attach such accessories as telephoto lenses and filters. Some cameras also have a digital zoom function, which allows zoom factors beyond what the optics can achieve. Don't be seduced by digital zoom figures, however. Because this feature essentially makes the pixels bigger, resolution actually decreases as the zoom factor increases.
Nearly every digital camera will have a small LCD — usually 2" or smaller, measured diagonally — that allows you to preview the pictures you're about to take or have already taken. You can then discard any that didn't turn out. Depending on the model, its screen may also function as the viewfinder, or it might have a traditional optical viewfinder. These LCD screens, usually color, consume a lot of battery power. Some models with traditional eyepiece viewfinders allow you to turn off the LCD.
In point-and-shoot models, the eyepiece is completely separate from the lens construction. Accordingly, what you see through the viewfinder is not quite what the camera actually captures. With models that have an SLR design, however, the image seen through the viewfinder is identical to what ends up on the CCD.
Size, power and suitability
Digital cameras don't require the big batteries used by camcorders. Because most take AAs, either single use or rechargeable, weight isn't likely to be a major concern. However, cameras do eat batteries quickly, making rechargeables highly desirable extras. But many camera makers don't include rechargeable batteries; you must buy them separately. If your decision comes down to price, check to see if rechargeable batteries and a charger are included with the camera.
When it comes to size, there are a few things you should consider. If it's a point-and-shoot camera, will it slip easily into your pocket? And if you're buying a camera with a zoom lens (a zoom lens inevitably makes the camera bulkier), is its weight properly distributed? Where is the lens positioned? Is it on the front of the camera or on its side? Which do you prefer?
You should also determine whether the camera's controls are placed within easy reach of your hand. And is it relatively easy to distinguish the different buttons by feel alone?
Try taking three or four pictures and then scrolling through the images on the LCD. Is navigation intuitive? Is it easy to determine whether you're about to save or delete an image?
If you're considering a model with a wide range of user-variable settings (such as zoom, focus and exposure), are they adjusted by external controls on the camera or lens assembly, or do you make adjustments electronically using on-screen menus and icons? Again, which approach are you more comfortable with?
Most digital cameras resemble SLRs, but high-end models from Agfa, Nikon and Philips use a swivel design, wherein the lens/flash is able to swivel 270 degrees from the LCD/battery section. This allows you to take shots from any position, much like using a camcorder with swing-out LCD.
It's also worth noting that the quality of the lenses themselves play a significant role in the quality of the camera's output. In general, it's fairly safe to assume that traditional camera makers make better lenses.
For more information
For more on retail outlets, check out our where to buy Digital Cameras
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