DSLR sensors have a special filter for IR light; a little hacking is all it takes to strip away that filter and modify the camera for awesome infrared photography.
Jerry, over in the forums for the Home Shop Machinist, shares his crash course in converting an old Pentax DSLR into an infrared unit. He had an old DSLR laying around and decided, upon purchasing a new one, that the old one was destined for hacking greatness. By taking the camera apart, removing the infrared filter, and then replacing it with a piece of specialty glass to enhance his IR photograph exploits, he was able to convert the old camera into a pretty sweet IR DSLR. The photo above is one of his sample shots.
Hit up the link below to read more about his build. Even if you have a different brand camera the basic premise is the same. As long as you’re comfortable hacking a camera apart and doing some heavy searching to find specifics for your brand and model, you’re one weekend project away from cheap infrared photography.