Most modern digital cameras can pull double-duty as webcams. Many cameras include model-specific information in the owner's manual and supply necessary software on a bundled CD, which is the preferred method for installation. In cases where the manufacturer didn't include this information, the specific equipment and software needed varies depending on your camera and computer.
Equipment You Need
You need a video cable, such as an HDMI or composite, and/or a USB data cable. See the documentation that came with the camera for specifics. In cases where your computer has USB ports but not a video-in port or your camera doesn't support video-out via USB, a USB video-capture device may also be necessary. If your camera or computer doesn't have a built-in microphone, an external microphone is also required.
Software You Need
The software you need depends on how you connect the camera to your computer. For connections using a video cable, little or no additional software is required.
For direct USB connections, install the camera's USB drivers. In many cases the drivers are included on a bundled CD, along with other software. Usually, if the camera supports webcam functionality natively, webcam software or webcam drivers may also be included. If webcam software isn't included, several third-party apps like ManyCam and Sparkocam may work. Check the app's website or documentation to see if it's compatible with your camera.
For connections using a USB video-capture device, install the capture device's included software. This software includes drivers for the USB devices and usually webcam software.
How to Set Up
Connect your camera's power adapter to the wall socket and then to your camera. If your camera doesn't feature a power adapter, make sure you have charged batteries inserted.
For video cable connections, connect a compatible video cable to your camera's video-out port and then connect the other end to your computer's video-in port. Typically, supported types include HDMI, mini-HDMI and composite analog video.
For USB connections, connect a USB cable to your camera's USB port and then to a USB port on your computer.
For USB video-capture devices, connect the capture device to your computer's USB port and then connect the device to your camera with a compatible video cable.
Switch your camera to Camera, Movie or Video mode and turn on the camera.
If you're using a separate microphone, connect it to your computer using the 3.5 mm microphone jack on your computer or an available USB port if you're using a USB microphone.
How to Enable Your Camera
After your camera is connected, select it as a camera using your favorite apps. Typically this option is found in the Options, Settings or Preferences menu of most apps.
As an example, for Skype click Tools in the Skype menu, followed by Options. Select the Video Options tab and choose your webcam from the Select Webcam drop-down menu.