As an example of how the photophysics under incoherent light differs from that induced by short, coherent laser pulses, consider the cis-trans photoisomerization of retinal, studied with MQC-PE in reference [25]. It is well-known that after an instantaneous excitation, cis-retinal may isomerize into trans following an exponential distribution within 200 fs time constant and 0.65 quantum yield like it does in bovine rhodopsin. Nevertheless, MQC-PE shows that it takes 42 s of continuous solar irradiation to populate the excited states of a single retinal molecule, which is dramatically distinct from the instantaneous-excitation picture. In the vision mechanism, this slow excitation is compensated by the large number of retinal molecules in the cone cells.