When I first started with a non point and shoot, I really struggled with the concept of f-stops.
I mean - the bigger the number the smaller the hole? But does that mean a wide depth of field (DOF) or a narrow DOF. And what does DOF really mean anyway?
DOF is depth of field. It is how much of your image is in focus - how much of the image 'plane'.
Ok - but what does that MEAN?
Try this for a brief explanation: (will open in a new window).
Once I actually understood DOF, I had to continually think about it when setting apertures. "If the number goes up - or down - what does it do to my DOF?"
So, todays quick tip - think of your aperture this way. The smaller the number, the narrower the DOF, the bigger the number, the wider (bigger) the DOF.
So, if you wish to isolate something in your image, you need a narrow DOF - a smaller number.
Zoom vs wide angle complicates the whole DOF thing - get to know your lens and the effects aperture has on DOF at each setting. But that is another post . . .