Beecher's Handouts /
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#3 - Depth-of-field
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Why Are
You Doing this Assignment?
Depth-of-field is one of the
major composition tools.
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If you're using a point-and-shoot camera, do close-up photography
of flowers, vegetables or ?
Because point-and-shoot cameras have lots of depth-of-field,
you can't experiment with using less or more depth-of-field.
If you're using a digital SLR, read on.
Do the Following
Photograph a still life using different lens openings.
Avoid Camera Shake
Set your camera on a table.
Why?
You won't get blur from camera shake.
You'll be using physically small lens openings.
There'll be little light coming through the lens opening.
So, the camera will select a long shutter speed in order to let
more light reach the sensor.
Setting your camera on a table will allow you to use slow shutter
speeds.
Composition
Set up the still life on the table.
Use three objects.
Space them about a six inches apart.
Object #1 is the closest to the camera, object #2 is further
away, and object #3 is the furthest.
Figure Out How Your Lens
Does Close-ups
Most lenses focus closely when the focal length is telephoto.
Experiment.
Zoom your lens to a wide-angle focal length.
See how close you can get to your still life.
Then, zoom your lens to a telephoto focal length.
Again, see how close you can get to your still life.
Then, use the focal length that's best for close-up photography.
A or Av
Use the aperture priority exposure mode: A or Av.
You'll select the lens openings.
The camera will set the shutter speed.
Focus
Focus on the middle object in every photograph.
If your camera chooses where to focus, make sure it is
focusing on the middle object.
If it isn't, replace the middle object with a taller object.
If the camera still chooses to focus on one of the other
objects, switch to manual focus.
There's a switch on or near the lens labeled AF/M.
Switch it to M.
To focus, turn a ring on the lens barrel until the middle
object is sharp.
Try Different Lens Openings
Photograph your still life using different lens openings.
Make sure the camera is sitting on the table.
You can write the lens openings on cards, and place them in
the scene.
You'll see how:
• Wide lens openings, such as f/4, have less depth-of-field.
• Smaller lens opening, such as f/22, have more depth-of-field.
