A number of sources for glass IR filters can be found after a brief search of the Internet. The camera stores that have a deep range of inventory will likely have a variation of an 87, 87C or 88A infrared filter in a size you can adapt to your camera. Of these, the 87C is the deepest and with it only IR light will make it into your shot.

With the filter in place the exposure may be as long as a full second in bright sunlight. Time to shoot at elevated ISO. Time to use a tripod, too.

IR light passes into the camera and onto the imaging chip. Most of the red, green and blue filters (or magenta, cyan, yellow and green filters in Canon digital cameras) at the surface of the chip are fairly IR transparent. The live monitor on many digital cameras will help. The black and white image from the camera will help you compose infrared images in the same way it helps to compose color images, except you are seeing IR directly through the camera, live.

A self timer will help with long exposures and the camera's autofocus will help. Infrared wavelengths are longer and focus at a different distance behind the lens. If you want to set the camera at infinity, choose a distance of ten feet instead. Since lenses behave differently, some experimentation may be required.

For a real treat, use a Wratten gel filter between the camera lens and an accessory lens. Now you can shoot telephoto and wide angle images in infrared. Here's an image made on a Nikon 950 with a Wratten 88A filter gel sandwiched under Nikon's fisheye lens.



Now that fisheye infrared images are possible with a digital camera what's next? IR VR?

In order to get a neutral grayscale image like this you will need to do one last thing. White balance to the IR image using the manual or preset white balance controls of your camera.

http://www.dpreview.com/learn/?/Photography_Techniques/Infrared_Photography_01.htm