Can a Gravitational Lens Magnify Gravity? A Possible Solar System Test
  Can a gravitational lens magnify gravity? Leading theories of gravity likely indicate "no", but the possibility might be testable by using our Sun as a gravitational lens and carefully aligning a satellite past the minimum transparent focal distance of about 25 AU. Here the magnitude of a maximal effect is estimated and found potentially observable. 
Robert J. Nemiroff (Michigan Tech)