More on Depth of Field

To emphasize the effect of the f number on the depth of field I have produced a photo of my bit of plumbing (in situ). The waste connector is in a wooden sink and I have shot it at an angle to show what the depth of field is at f3.5 and then at f9.5.
You need to click on the image to open it up to full size and then you will see the difference a couple of f-stops can make.