# Doppler Shift in terms of energy

Energy of a photon is $E=nhf$ where $n$ is an integer number, $f$ is a frequency and $h$ is Planck's constant. When a moving light source radiates blue light the wave will appear at two difference frequencies when observed toward the point the source is moving and at the point from which the source is getting further away right? Does it mean that the photons going into two different directions will have different energy levels? The same source different energy photons. I do not understand something here....

First of all the energy of a photon is $=hν$ where $ν$ is the frequency of light that will become manifest if there is an accumulation of n photons building up a classical electromagnetic beam. Photon energy itself covers all the realm of positive real numbers, as all energies.