Our eyes are tuned to see the visible spectrum of light, a term used to refer to light with wavelengths between 380 and 750 nanometres. Just because we cannot see any light at night does not mean that there is no light there. Infrared light---light with a wavelength longer than 750 nm---though invisible to the naked eye is visible to cameras. Digital cameras use a special filter to block this infrared light, but with a few modifications to your existing camera, you can build your own night vision camera capable of "seeing" and recording infrared.
Select a digital still or video camera---including webcams---that you would like to modify to a night vision camera. The modification is irreversible and the camera will no longer be able to shoot normal colour photos or videos. Film or tape cameras will not work, as neither standard film nor videotape will render infrared light correctly. You will need special film or tape to shoot infrared with a nondigital camera.
Consult your camera's manual to determine the location of the camera's image sensor. It will be labelled either as a CCD or CMOS sensor.
Open your camera, removing screws with your screwdriver if necessary. Even though you can expose a dSLR (digital single lens reflex) sensor by removing the lens, it will be necessary to remove the back of the camera to get to the infrared filter. Video cameras will also need to be opened to access their sensors. Webcams often must be pried apart if their components are attached with clips or glue.
Remove the red-tinted glass that covers the sensor. This is the infrared filter. It will likely be attached to the camera or sensor in some way, so you will need to remove it without damaging the sensor or camera. You can usually slip your screwdriver between the filter and sensor and gently pry the filter off. Be careful to keep the screwdriver from scratching the sensor.
Discard the infrared filter, and reassemble the camera. If you needed to break apart a glued component on a webcam, you can use an adhesive to reconnect the pieces. Digital still cameras and video cameras can be reassembled without replacing any parts.
Take photos or video as usual, remembering that your camera is now capable of seeing more than your naked eye can. Because the modification occurs between the sensor and the lens, you will not be able to see the difference through your camera's eyepiece. Any digital display will show infrared light, however.
Use your infrared flashlight to put more infrared light into your shot and make your subject even more visible. During the day, or when photographing living subjects---as organic material throws off much more infrared light than inorganic material---this flashlight is not necessary, but it will illuminate nonliving subjects at night without casting any visible light.
After following these steps, your camera will be sensitive to both visible and infrared light. To render pictures more sharply and without interference from visible light, you can either purchase a visible light filter to connect to your still or video camera's lens, or attach an exposed piece of film to the sensor where the infrared filter was located.
These modifications can damage your camera and will void any warranty. The modification is irreversible. It will prevent the camera from taking normal pictures unless another infrared filter is used. Do not attempt these modifications on any camera you are not willing to lose.