When I realized that my Nikon cannot be modified into an IR camera, I contacted a dealer in Europe and purchased a metal tube which screws around the Nikon lens, along with a 52mm IR720 lense which screws into the front of the tube.The tube is deep enough to allow the camera lens to come forward without bumping into the IR filter. Unfortunately the tube surrounds the image and depending on the zoom I use causes the image to be round rather than square.

I let the camera calculate the exposure in each case.