I took pictures using portrait mode on my camera and saw how by clicking on one subject everything else around it is out of focus. These photos I took with the regular camera mode and did the same thing by clicking on the subject. In the first one Iron man is sharpness more and in the second one he’s not as sharp.
The assignment was to NOT use portrait mode and get shallow depth of field in the photo mode. To do this you need to get closer to the front subject.