so lets say i take a small lcd, and stick a lens in front of it. a magnified image will be projected on a wall. now lets remove this wall and stick a camera a little behind where the image is formed (so the projected image is supposed to fill the whole field of view of our camera). the image doesnt fill up the cameras sensor. instead, the camera only sees the magnified part of the object only inside the first lens thats far away. the camera still sees everything around this lens.
now if ive placed a real object where the supposed projected image is supposed to be, then that does fill up my cameras entire field of view.
ive drawn an image. according to the ray diagrams, i expected to have this image fill up the camera sensor. this is not my result.