A Geometrical Approach to Strong Gravitational Lensing in f(R) Gravity
  We present a framework for the study of lensing in spherically symmetric
spacetimes within the context of f(R) gravity. Equations for the propagation of
null geodesics, together with an expression for the bending angle are derived
for any f(R) theory and then applied to an exact spherically symmetric solution
of R^n gravity. We find that for this case more bending is expected for R^n
gravity theories in comparison to GR and is dependent on the value of n and the
value of distance of closest approach of the incident null geodesic.
