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In a short period of time, digital camera prices have gone from levels that made them the province of a few wealthy technogeeks to being competitive with a wide range of electronic consumer goods. Because digital cameras interface with computers, Comp-TIA A+ certified techs need to know the basics.

Storage Media—Digital Film for Your Camera

Every consumer-grade camera saves the pictures it takes onto some type of removable storage media. Think of it as your digital film. Probably the most common removable storage media used in modern digital cameras (and probably your best choice) is the Secure Digital (SD) card (Figure 18-35). About the size of a Wheat Thin (roughly an inch square), you can find these tiny cards with capacities ranging from 64 MB to more than 1 GB. They are among the fastest of the various media types at transferring data to and from a PC, and they’re quite sturdy.

Figure 18-35 Secure Digital card

Connection

These days, almost all digital cameras plug directly into a USB port (Figure 18-36). Another common option, though, is to connect only the camera’s storage media to the computer, using one of the many digital media readers available.

You can find readers designed specifically for SD cards, as well as other types. Plenty of readers can handle multiple media formats. Many computers come with a decent built-in digital media reader (Figure 18-37).

Quality

As with scanners, you should consider the amount of information a particular model of camera can capture, which in the digital camera world is expressed as some number of megapixels. Instead of light-sensitive film, digital cameras have one CCD (charged coupled device) or CMOS (complementary metal-oxide semiconductor) sensor covered with photosensitive pixels (called photosites) to capture the image; the more pixels on the sensor, the higher the resolution of the images it captures.

Figure 18-36 Camera connecting to USB port

Figure 18-37 Digital media reader built into computer

Not so long ago, a 1-megapixel digital camera was the bleeding edge of digital photographic technology, but now you can find cameras with 10 times that resolution for a few hundred dollars. As a basis of reference, a 2-megapixel camera produces snapshot-sized (4 × 6 inch) pictures with print photograph quality, whereas a 5-megapixel unit can produce a high-quality 8 × 10 inch print.

Another feature of most digital cameras is the capability to zoom in on your subject. The way you ideally want to do this is the way film cameras do it, by using the camera’s optics—that’s the lens. Most cameras above the basic level have some optical zoom—meaning the zoom is built into the lens of the camera—but almost all models include multiple levels of digital zoom, accomplished by some very clever software in the camera. Choose your camera based on optical zoom: 3× at a minimum or better if you can afford it. Digital zoom is useless.

Form Factor

As was the case with film cameras, size matters on digital cameras. Digital cameras come in several form factors. They range from tiny, ultra-compact models that readily fit in a shirt pocket to monster cameras with huge lenses. Although it’s not universally true, the bigger the camera, the more features and sensors it can have. Thus bigger is usually better in terms of quality. In shape, they come in a rectangular package, in which the lens retracts into the body, or as an SLR-type, with a lens that sticks out of the body. Figure 18-38 shows both styles.

Figure 18-38 Typical digital cameras

Web Cameras

PC cameras, often called webcams because their most common use is for Internet video communication, are fairly new to the world of common I/O devices. Too many people run out and buy the cheapest one, not appreciating the vast difference between a discount webcam and more expensive models; nor do they take the time to configure the webcam properly. Let’s consider some of the features you should look for when buying webcams and some of the problems you can run into