Infrared photography is a photographic technique that allows only for infrared light to an image, blocking out all other natural light. Infrared light is essentially the lighted heat emissions that rise off a subject. Infrared photography is very good for capturing heat light from plants, trees and human beings. Images captured on infrared film appear to be black and white, but the image actually displays the contrast between heat and non-heat. Infrared photography is achieved through the use of a highly specialized filter.
Most of today's digital cameras have anti-infrared mechanisms built right into them, because heat is picked up naturally by a digital camera. This is obviously a hindrance to the photography looking to specifically achieve an infrared photograph. There are ways that infrared photography with a digital camera can be achieved. You can use an infrared filter on a 2 or more mega pixel digital camera. This may require excessive exposure time, and you may pick up some undesired graininess. Digital infrared photographs can also be altered in a software editing program.