Photons of our visible colors have mass. They could not refract into the visible colors if they did not. A photon of our visible colors; has the color code of refraction; and when it impacts a convergent lens; its specific diameter of axis of spin; violet thru red; demands an exact angle of refraction. Picture the photon as a circular impactor to the glass of the lens. It can only refract sharply; if its axial diameter is small; as is a mass of violet light. Red light photons have a larger mass; and must have a larger diameter of axial spin; and must therefore refract at a larger angle; because the larger diameter can not allow for that much mass to turn as sharply as a small diameter axial mass; like a violet light photon.

Not only do they have variations of mass; but the spectral photons have variations of rates of spin. Yes, their forward speed is the same; in a vacuum; but they have a variable, but harmonious, spin variation.

Violet, having the smallest diameter of spin; can therefore refract at a very sharp angle; forming a focal spear of light with its point of focus; very close to the convergent lens. Where a red light is focused further out from the lens; with its point of focal cross or spear point of focal being the focal farthest out from the lens.
The effect is that a convergent lens has a sequence of focal points of the different colors; of violet thru red; with each spear point of color in a colored spear of light. Seven colors equals seven spear points each in sequence, one inside the focal spear of the next. That refraction sequence is also shown in the refractory spins around the lens where birefringence is expressed as rings of the rainbow colors.