Hello, This is my first post and I have one question. My major is not physics. For now, I am struggling to understand general relativity for own reason because the math involved is troublesome to me but facing one question I need to figure out. It is related with the gravitational lensing effect. I made a picture to help you understand my question better. I heard that Einstein's general relativity provide the most correct picture about the geometrical curvature of space-time and mass is the source to warp fabric space-time. So light emitted from distant galaxy always moves straight line on the flat surface of space-time in vacuum but straight line on the warped surface of space-time in gravitational field near sun. My question is that is there any change in the frequency or wavelength of beam bent within gravitational field near sun? Let me describe morel from the picture above. Lets assume that a ship with double gun laser far away from sun and single laser source with frequency f1 at position p1 shoot laser beam through two gun at the same time to the direction of sun such that two beams bend slightly differently and passing through p2 for upper gun and p3 for lower gun. The path from p1 to p2 is equal length with the path from p1 to p3. The energy of two beams emitted from the ship is ##E = hf_1 ## . With such preparations, let suppose two observers are positioning at p2 and p3 and their watches are synchronized already such that they can start and complete measurement at the same time. Time synchronization is required due to the gravitational time dilation. Their task is to measure the frequency of the light beam from the ship. Now here is my question. What is the relation between f2 and f3? Are they same or different? If different, which one is higher? What general relativity predict? Is there any experimental results? My best guess is what general relativity predicts would be f2=f3 but not sure. I would appreciate for any help or guide.