APERTURE controls the depth of focus by opening or closing the camera iris.

This means that when you change your lens opening you can increase or reduce the depth of focus. That is what matters to your composition and photographers eye.

Because the lens aperture controls the iris and how much light is available FAST photographers must avoid over or underexposure–which brings about a technical problem.

DSLR Tip:  Changing the APERTURE requires you make a corresponding change to the SHUTTER speed to maintain proper exposure. These two camera controls APERTURE and SHUTTER are designed to balance each other by controlling the quantity of light. APERTURE controls depth of focus and SHUTTER controls motion. Change one you have to change the other. Simple as that.

Note:  You may have heard about APERTURE priority or SHUTTER priority modes often found on DSLR cameras. Clearly this is techno-speak for depth of focus priority or motion priority.

Compact Digital TIP:  FAST photographers constantly make thoughtful choices and so must balance APERTURE’s focus control with SHUTTER’s motion control.
Smartphone Tip:  It is possible to manage these same features using Scene Modes./ / / Article update: coming soon.

Your first thought in FAST picture taking is to FOCUS attention and create crisp imaging on your subject. The second step then is to decide if you need to control additional depth or control the effect of motion on your subject.

  • APERTURE controls quantity of light and the depth of FOCUS
  • SHUTTER controls quantity of light and the expression of motion
  • APERTURE and SHUTTER are linked in a 1:1 relationship
  • One step of APERTURE is equal to one step of SHUTTER
  • If you reduce APERTURE you must increase SHUTTER and vice versa
  • IF Depth-Of-Focus is priority for your picture then manage APERTURE first
  • IF Expression-Of-Motion is priority for your picture then skip to SHUTTER now

Take note!

HELP if you need to understand this technical aspect of photography there is a great video here.
  • If you want to control depth of FOCUS you need APERTURE priority.
  • If you want to control motion you need SHUTTER priority at the expense of focus depth.

Practice balancing the changes between APERTURE and SHUTTER so that it is something you can do FAST.

The image of the Coffee Worker has a very high depth of focus while the landscape of a Coffee Plantation has a very selective depth focus.

/ / / Article update: I will add some practice APERTURE assignments soon.


  • A usually adjustable opening in an optical instrument, such as a camera or telescope, that limits the amount of light passing through a lens or onto a mirror.
  • The diameter of such an opening, often expressed as an f-number.
  • The diameter of the objective of a telescope.

/ / / Article under construction -> Reviewing this article on 26 May ’14 I see some improvements to make soon. <- / / /

  Shoot FAST
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