Newtonian gravitational lensing (not sure if that is an actual term). Newton's gravity could be applied to photons to get some lensing, but this predicted was half of that predicted with general relativity
> A naive application of Newtonian gravity can yield exactly half this value, where the light ray is assumed as a massed particle and scattered by the gravitational potential well.
https://en.wikipedia.org/wiki/Gravitational_lensing_formalis...