I have been interested in infrared photography for a few years.  Recording light from outside the visible spectrum, it can show the world in a different perspective.  Foliage reflects a lot of infrared, so it turns pale.  Sky and water do not, so they become dark.  The degree to which this happens depends on the strength of the infrared filtration, but it does result in surreal images which have a lot of contrast when converted to monochrome.  Alterrnatively, it is possible to create false colour effects using an image editing application such as Photoshop.

I originally started with an unmodified camera and an infrared filter over the lens.  This blocks light from the visible spectrum and only allows infrared light to pass which a digital sensor can record.  Since infrared light interferes with focus and colour, manufacturers filter it out which means that this method is not very efficient.  The filter on the lens removes light from visible specftrum, while a filter over the sensor blocks the infrared light which has been passed.  The end result is that very few photons actually reach the sensor as the filters cancel each other out.  The camera I initially used had weak infrared filtration which meant that I did not get extended exposure times and could handhold, but I quickly progressed to a modified camera which was easier to use.