Suppose we have a camera with a focal point at (0,0,0) and an image plane of x+z=2.
a. A point that is somewhere in the scene appears at the image location (3/2,3,1/2). If we took a picture using a camera with the same focal point but an image plane of z=1, where would this scene point appear in the image?
b. Suppose the scene point appears at the image location (xy.z), with x+z=2. Suppose we took a picture using a camera with the same focal point but an image plane of z=1. Give a general formula that tells us where this point will appear in the image.