The digital photography revolution has changed photography forever, including the language used to speak about the craft. Below are a few key words used in digital photography.
Megapixel: A megapixel is one million pixels. If a camera is a 6 megapixel camera, this means that the image sensor inside the camera contains a total of 6 million individual pixels which work together to record each photograph. More pixels means higher resolution. Higher resolution translates into crisp photographs, rich in detail. The images below show the relationship between the images shot with a 6 megapixel camera (top) and a 3 megapixel camera (bottom).
Interpolation: This refers to the process of artificially enlarging a photograph, which is usually done on the computer. A word of caution: Interpolating an image can be both good and bad. It can be good because interpolation can be used to make photographs larger; however, it can be bad because it can diminish the quality and clarity of the photo. For example, if the smaller image was interpolated in order to make it the size of the click-through photo, quality would be lost. The result might resemble the one below, which looks "soft."
Resolution: Imagine a 4-by-6 photo that has 300 dots per inch (dpi). This photo has double the resolution of the same photo that has 150 dpi. Therefore, resolution can be thought of as the total number of pixels contained in a photo.