Most electronic image sensors are sensitive to infrared light.  Digital cameras usually include IR blocking filters so that it doesn't corrupt the image in the visible spectrum, but retain some IR sensitivity to varying degrees.  By using a filter that blocks the visible light and passes IR you can get pretty good results with some cameras.  The Fuji S2 is not terrific in this regard and requires fairly long exposures (about 1/2 second in this case).  You can't see anything through the viewfinder, so you have to compose the shot without the filter.

Shot with the Fuji S2 and Sigma 28/2.8.