I've often heard the speed of light and time dilation related from the standpoint of a particle as being in constant motion at the speed of light with the vector rotated slightly off the temporal dimension and toward any combination of the three spatial dimensions. Does this mean photons experience no time? How does this relate to redshift seen over large distances? Does the photon still experience a slight amount of time to be redshifted? If photons experience some small quantity of time, is there a way to calculate the actual constant speed through spacetime?