When I wrote a short primer on HDTV a couple of weeks ago, the response convinced me that this is a great time to review the technologies that are most likely to find themselves gift-wrapped this year.
Although digital cameras have been around for a decade now - and many buyers are on their second or third - I still get lots of questions about them. So here's the 2007 holiday version of Digital Cameras in a Nutshell:
Instead of using film, digital cameras record images on a grid of light-sensitive dots, usually a charge-coupled device, or CCD.
Once it records an image, the camera stores it on a flash memory card. A typical one-gigabyte memory card can store hundreds of photos. Most cameras have a liquid crystal display (LCD) on the back that allows you to frame shots, review photos stored on the card and erase bad pictures.
You can transfer photos to a PC by connecting the camera directly with a USB cable, or by inserting the memory card into a reader built into the computer. On the PC, you can touch up and crop each photo, then print it directly, transfer it to an online printing service or e-mail a copy to friends or family. Some printers don't require a PC middleman: They can print directly from a camera or memory card.
Once you've stored and backed up your photos you can erase the memory card and use it again.
How are digital cameras different from each other?
You'll find digital cameras with price tags ranging from $90 to $5,000, although most are in the $200 to $600 range. The main differences involve the resolution of the images they record, the type and quality of the lenses, the mechanics they use for taking pictures, and the options they provide for controlling exposure.
Resolution is the first item you'll see in a camera ad or spec sheet. It refers to the number of dots, or pixels, that the camera uses to record an image. The more dots, the greater the potential detail. Resolution is expressed in megapixels, or millions of dots. Today's cameras start at 6 megapixels and head upward to 12 megapixels or higher.
More pixels are better, but only up to a point. Even a 5-megapixel camera with a decent lens will produce great 4x6 snapshots and beautiful 8x10 enlargements from a full frame. But if you want larger prints - or quality prints from cropped images - a 7 to 8 megapixel camera is a better buy. You'll find plenty of these from top manufacturers in the $200 range.
Types of cameras
There are four main classes of cameras and a lot of overlap in prices and features. But most photographers would agree on these categories:
Subcompacts ($150 to $600): These tiny, point-and-shoot wonders are my favorites because they fit in a shirt pocket and deliver great images with minimal hassle. Most have 3-to-1 zoom lenses and flashes that are adequate for small groups but tend to wash out beyond seven or eight feet. They have a variety of "scene" settings for beach photos, portraits and so forth, but most can't set the aperture and shutter speed independently. If you're a beginner and want a camera to take on vacation, look no further.
Compacts: ($200-$700): These cameras are slightly larger than subcompacts - but many are still small enough for a jacket pocket or purse. The extra size actually makes them easier to hold steady. They often have more powerful flashes than their little brothers, and some have more versatile zoom lenses - offering wider-angle shots at one end and tighter zooming at the other. Better models also have more versatile light metering and independent controls for shutter speed and aperture.
Super-zooms ($300-$700): These often look like traditional single-lens reflex cameras and have many of the same features - but without interchangeable lenses. Instead, they have capable, built-in zoom lenses with ratios of 10-to-1 or more and better light-gathering capability than smaller cameras.
Most offer full exposure control, and some will accept external flash units. Super-zooms are a bit more expensive than good compact cameras, and considerably heavier.
If you don't want to carry a camera on a strap around your neck, stick with a compact.
Single-lens reflex: ($600 into the thousands) These bulky superstars are digital versions of traditional SLR cameras from top manufacturers such as Canon, Nikon, Olympus and others. Like their film counterparts, digital SLRs allow you to view your image through a mirror connected directly to the lens - so you see exactly what you're taking.
One reason they're bulky is that they accept interchangeable lenses. In fact, they're often sold as naked camera bodies - with lenses sold separately. Digital SLRs are popular with film photographers because they can use many of the lenses they already own.
Digital SLRs are not for the faint of pocketbook, but if you want to duplicate the experience of a film SLR with the advantages of digital photography, this is the way to go.
All but the cheapest and most expensive digital cameras come with a zoom lens, typically a 3-to-1 or "3X" lens. This is the equivalent of a 38-to-105 millimeter zoom on a typical point-and-shoot, 35mm film camera.
More X's (as in 10X or 12X) mean greater zooming power. Careful, though. Most camera spec sheets report two zoom levels - optical and digital.
Optical zoom is the one that counts. Digital zooming is a trick that blows up pixels to produce lousy photos. But manufacturers will often add the two to make the camera seem better than it is. Don't be fooled.
For more information: You'll find exhaustive reviews of digital cameras on the Digital Photography Review site (www.dpreview.com). For less technical but well-informed reports, check out the Cnet Web site at http:--reviews.cnet.com/ digital-cameras.