  We report on the detection of single photons with {\lambda} = 8 {\mu}m using
a superconducting hot-electron microbolometer. The sensing element is a
titanium transition-edge sensor with a volume ~ 0.1 {\mu}m^3 fabricated on a
silicon substrate. Poisson photon counting statistics including simultaneous
detection of 3 photons was observed. The width of the photon-number peaks was
0.11 eV, 70% of the photon energy, at 50-100 mK. This achieved energy
resolution is one of the best figures reported so far for superconducting
devices. Such devices can be suitable for single photon calorimetric
spectroscopy throughout the mid-infrared and even the far-infrared.
