Aphotographer uses his camera, whose lens has a 70 {\rm \; mm} focal length, to focus on an object 5.0 {\rm \; m} away. he then wants to take a picture of an object that is 50 {\rm \; cm} away. part a in which direction must the lens move to focus on this second object? in which direction must the lens move to focus on this second object? toward the film away from the film request answer part b how far must the lens move to focus on this second object? express your answer to two significant figures and include the appropriate units.