Focus - focus with different apertures

At this exercise I was suppose to focus on a object with its background and by changing f-stops (aperture values) achieve different look.

I have chosen to photograph two standing lenses on a table. I have focused on the one in the foreground. By changing my aperture value I could accomplish every time different look. 

When I used wide aperture, f-number (f-1.4), the lens I focused on was perfectly sharp, but the other one in the background was way out of focus. By stepping down to f-4 my picture changed. I didn't change my focus point, but my background lens was more in focus. And as I stepped down to f-8 and than to f-16 the lens in the back became more and more in focus.

By blurring the background we can make sharp objects to stand up against the background and draw attention to them.

This demonstrates how the simple change of aperture value can change the look of the picture and by blurring the background we can draw attention to the desired object in foreground.

 f 1.4

f 4 

 f 8

f 16