Response times refers to a series of times, or delays, which appear as the natural properties of a digital camera. They include the initialing time, shutter lag, and delays from shot to shot.
For various digital cameras, you may find different response times. It can be pretty annoying to have the slow response times because you may not be able to capture several spontaneous images. Commonly, the response times are slower for inexpensive, entry-level digital models versus expensive, high-end digital models.