Controlling Depth of Field
Change aperture to change your depth of field
This next point is very important, so make sure you understand it before moving on:
You increase or decrease the depth of field in your photographs by changing the aperture setting on your camera. Aperture changes are measured in f-stops.
Just think of aperture f-stops as a measurement like degrees or inches. Here is a complete series of f-stop numbers, from small to large:
1.8 2.0 2.5 2.8 3.5 4.0 4.5 5.6 6.7 8.0 9.5 11 13 16 19 22 27 32
This is how aperture f-stops relate to depth of field:
SMALL F-STOP NUMBER = SMALL DEPTH OF FIELD
LARGE F-STOP NUMBER = LARGE DEPTH OF FIELD
Let's go back to the illustrations to understand this a bit better.
Illustration Four — Small Depth of Field
- This illustration shows a SMALL depth of field
- On your camera, this might be equivalent to an aperture setting of f4.0
- Items B and C are in focus since they are on the plane of focus
- Item D is also in focus since it is within the depth of field
Illustration Five — Medium Depth of Field
- This illustration shows a MEDIUM depth of field
- On your camera, this might be equivalent to an aperture setting of f8.0
- Items B and C are in focus since they are on the plane of focus
- Items D and E are in focus since they both are within the depth of field
Illustration Six — Large Depth of Field
- This illustration shows a LARGE depth of field
- On your camera, this might be equivalent to an aperture setting of f22
- Item A is in focus since it is on the plane of focus
- Items B, C, D and E are in focus since all of them are within the depth of field
Here is the relationship between f-stops and depth of field again:
SMALL F-STOP NUMBER = SMALL DEPTH OF FIELD
LARGE F-STOP NUMBER = LARGE DEPTH OF FIELD
Now I've added the f-stop numbers:
f4.5 = SMALL DEPTH OF FIELD
f8.0 = MEDIUM DEPTH OF FIELD
f22 = LARGE DEPTH OF FIELD
Here are the most common types of photos taken at different apertures:
f4.5 = SMALL DEPTH OF FIELD = Best for portraits
f8.0 = MEDIUM DEPTH OF FIELD = Good for most shots
f22 = LARGE DEPTH OF FIELD = Best for landscapes
Let's take a look at some photographic examples to help this sink in.