1/11/11 TUESDAY TUTORIAL

Last week I promised a little more on aperture, so here we go…

In photographic terms, aperture is the adjustable opening in the lens used to allow light onto the film or digital surface.  Aperture size is measured in F-Stops.  Larger openings (smaller numbers – f2) allow more light to hit the film surface.  Smaller openings (bigger number f/22) needs more light for proper exposure.

REMEMBER the relationship between F-Stop/Aperture and Depth of Field is:

  • ·Large F-Stop = Large Depth of Field = More Light Needed
  • ·Small F-Stop = Small Depth of Field = Less Light Needed

Depth of Field relates to the sections of your image, in front of and behind your main focus point that are in focus.   Depth of field is determined by several factors:

  • ·Aperture/F-Stop
  • ·Lens
  • ·Subject Distance

Since your camera is only able to focus on one space, depth of field allows a photographer to determine the area(s) of the image that will be in “acceptable focus” to the viewer.  For example, landscapes require a large depth of field, and consequently the entire image appears in focus.  In portraiture, a small depth of field is selected to blur the background and reduce distractions. So in practical term higher f-stops, like f/22, generally require slower shutter speeds and give images a larger depth of field.  Lower f-Stops, like f/2, will allow faster shutter speeds and give images a shallow depth of field.  Some examples follow:

Landscape - 18mm, f/16, 1/160th Foreground to background in focus

Portrait - 50mm, f/1.4, 1/125th Shallow depth of field, and blurred background

Depth of Field relates to the sections of your image, in front of and behind your main focus point that are in focus.   Depth of field is determined by several factors:

  • ·Aperture/F-Stop
  • ·Lens
  • ·Subject Distance

Next week we’ll discuss the lens and subject distance effect on depth of field.  Thanks for reading.

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