The photon energy is the energy carried by a single photon with a certain electromagnetic wavelength and frequency. The higher the photon's frequency, the higher its energy. Equally, the longer the photon's wavelength, the lower its energy. Photon energy is solely a function of the photon's wavelength. Other factors, such as the intensity of the radiation, do not affect photon energy. In other words, two photons of light with the same color (and, therefore, same frequency) will have the same photon energy, even if one was emitted from a wax candle and the other from the Sun.