And so, in the end, this was exactly the image I was hoping to make.  We’re trained as photographers to set our exposures according to the f/16 rule.  For those unfamiliar with the rule, it states that if you are shooting in bright sun, then you should set your aperture to f/16 and your shutter speed to 1 over your ISO.  I was shooting at 200 ISO on this day, so I should have set my camera to f/16 at 1/250 second.  But not on this day.  No not this day.  This day the assignment was to shoot at f/4.  Shoot everything at f/4.  And so all week I did just that.  I kept the aperture at f/4 and I visited shutter speeds that I’ve never visited before: 1/3000sec 1/4000sec.  Phenomenal.  Why?  What is the reward for doing that?  In fact it is something that no point and shoot camera can do … blur out the background.  That’s the whole point of the exercise.  And on this day it yields a single Cholla Cactus and the remainder of them pleasantly blurred out.