Connections

Downloading images from camera to computer requires some kind of connection. Among current digital cameras, four interfaces are popular—standard serial, optical, USB serial, and FireWire. The technical aspects of each are described in Chapter 11, "Ports."

The standard serial connection accommodates the widest range of computers but is also the slowest connection in general use. A so-called "high-speed" serial interface in the computer realm operates at a speed of 115,200 bits per second, a rate that may demand ten minutes to download the contents of a modest-size camera memory unit. (The Apple Macintosh fares a bit better—its standard serial interface can accept information about eight times faster, 921 kilobits per second.) Older digital cameras relied on serial connections, as do some inexpensive, low-resolution models. But serial connections are too slow to handle today's large image sizes.

Optical connections use the IrDA interface. Although serial in nature, an IrDA connection can handle data speeds up to 4Mbps. The chief shortcoming of optical links is the need for an IrDA interface at both ends of the connection. Although at one time every notebook computer had an IrDA interface, the interface is uncommon in desktop computers. Many manufacturers are omitting them from their notebook machines as well. Although the IrDA interface is fast and convenient, you'll want to ensure your computer can deal with it.

Most newer digital cameras take advantage of the Universal Serial Bus port design. The latest should use USB Version 2.0. This interface combines high speed with connection convenience. Even USB 1.0, which operates at about 12 megabits per second, is fast enough to empty a digital camera's memory card in a minute.

Digital video cameras usually use FireWire connections, which provided the only consumer-level connection system capable of handling video before the advent of USB 2.0. The FireWire connection has not caught on among makers of still cameras.