F-Stop

F/4
In this picture, we can feel that the foreground is very clear while the background is kind of blurry. This is because that the depth of field is smaller which means the camera focuses on the foreground and leaves the background intact.

F/11
With F/11, we can still identify the foreground and the background; however, compare to the on of F/4, this one is more clear in the overall because of the F-Stop. 

F/22
For this image, the background becomes clear comparing to the one of F/11 and F/4. The depth of field of the picture is longer than the one of F/11 and F/4 while shorter than F/32.

F/32
In this image, we can't really tell which part is clear and which is blurry because camera depth of field is larger which means the distance of focus is longer than the others.

Based on the experiments above, we can observe that different F-Stops results in pictures with various characteristics.