transferred to a computer later. This memory device is usually a memory card; floppy disks and CD-RWs are less common. In addition to taking pictures, digital cameras may also record sound and video. Some function as webcams, some use the PictBridge standard to connect to printers without using a computer, and some can display pictures directly on a television set. Similarly, many camcorders can take still photographs and store them on videotape or flash memory cards with the same functionality as digital cameras. Digital photography is an example of the shift from analog information to digital information. In the past, conventional photography was an entirely chemical and mechanical process that did not require electricity. Now, modern photography is a digital process in which analog signals are converted to and stored as digital data using built-in computers. Performance metrics The quality of a digital image is a composite of various factors, many of which are similar to those of film cameras. Pixel count (typically listed in megapixels, millions of pixels) is only one of the major factors, though it is the most heavily marketed figure of merit. Digital camera manufacturers advertise this figure because consumers can use it to easily compare camera capabilities. It is not, however, the major factor in evaluating a digital camera for most applications. The processing system inside the camera that turns the raw data into a color-balanced and pleasing photograph is usually more critical, which is why some 4+ megapixel cameras perform better than higher-end cameras. Resolution in pixels is not the only measure of image quality. A larger sensor with the same number of pixels generally produces a better image than a smaller one. One of the most important benefits of this is a reduction in image noise. This is one of the advantages of DSLR cameras, which have larger sensors than simpler point-and-shoot cameras of the same resolution. Additional factors that impact the quality of a digital image include: Lens quality: resolution, distortion, dispersion (see Lens (optics)) Capture medium: CMOS, CCD, negative film, reversal film Capture format: pixel count, digital file type (RAW, TIFF, JPEG), film format (135 film, 120 film), aspect ratio Processing: digital and/or chemical processing of "negative" and "print" Pixel counts The number of pixels n for a given maximum resolution (w horizontal pixels by h vertical pixels) is the product n = w × h. For example, an image 1600