We test the Nikon D40x with a Hoya R72 filter for its capability for infrared photography
For this test we took a Nikon D40x out with a Hoya R72 filter and a tripod into the field and tested its IR sensitivity.
This image as it comes from the camera was shot at 30 seconds, f3.5 and 100ISO
Taking the red channel to do a mono conversion and then using levels, we get the following result:
Unlike many other digitals, the blue channel is not markedly noisier than the green, as shown below. These are 100% sections of an image shot at 400ISO.
The D40x is a quite capable IR camera, so long as you engage with the joys of the long exposures.
A conversion from the green channel.