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Creative Controls, F-Stops & Depth of Field

landscape photo typically should have both the foreground and the background in sharp focus. The foreground is actually
20mm Nikkor F 16
50mm Nikkor F 2.0

50mm Nikkor F 11.00

more critical as it is what initially draws the viewer's eye and pulls it into the photo. Think about it, we are accustomed to seeing near objects more clearly than objects far away. Standing out doors you can clearly see the ground in front of you, while objects on the horizon are hazy.
For the photo of the boat, a 20mm lens was used. The F-stop was 16 with a focus distance of 3 feet. The resulting depth of field was from 1.7 feet to infinity. To further emphasize the boat in the foreground the camera height was approximately one foot above the ground.
F-stops determine the depth of field. The larger the F-stop number the larger the amount in focus. A lens set at F16 will produce more in focus than the same lens set at F4.
Another factor that affects depth of field is distance from the camera to the subject. Depth of field decreases as the camera moves closer to the subject.
The maximum amount of depth of field is achieved by using the largest f-number on the lens, typically F22 or F32. However lenses are not as sharp at their largest f-number as they are one or two numbers smaller.
F16 is a good compromise between sharpness and depth of field. The table demonstrates the depth of field available at F16 for various focal lengths. Notice that a small amount of foreground focus can be gained by focusing the lens at a shorter distance than infinity known as Hyperfocal Focusing. Most prime lenses have a hyperfocal scale on their lens barrel as an aid for adjusting for maximum focus. It is why we still use prime lenses instead of zooms.
For those of you shooting zooms use the table as a guide.
Enjoy,
Mike and Tammy Rice
|
Depth of Field |
Infinity Focus |
Hyperfocal Focus |
|||
|
Lens |
Aperture |
Focused Distance |
Depth of Field |
Focused Distance |
Depth of Field |
|
20mm |
F 16 |
Infinity |
3.0’-Infinity |
3.0’ |
1.7’-Infinity |
|
24mm |
F 16 |
Infinity |
4.0’-Infinity |
5.0’ |
2.4’-Infinity |
|
28mm |
F 16 |
Infinity |
5.3’-Infinity |
9.0’ |
3.0’-Infinity |
|
35mm |
F 16 |
Infinity |
8.3’-Infinity |
15.0’ |
5.5’-Infinity |
|
60mm |
F 16 |
Infinity |
22.0’-Infinity |
Infinity |
Infinity |
|
105mm |
F 16 |
Infinity |
67.0’-Infinity |
Infinity |
Infinity |