What do you notice when you change the diaphragm openings?

Changing the diaphragm openings affects the depth of field in your photographs. A larger diaphragm opening (lower f-stop number) results in a shallower depth of field, which creates a more pronounced background blur. On the other hand, a smaller diaphragm opening (higher f-stop number) increases the depth of field, keeping more of the scene in focus.