Aperture

1. Depth Of Field

2. Aperture and Depth
Depth of Field

3. The Depth of Field is a measure of how
much ‘depth’ of an image will be in focus.
An image with large depth of field will have much of the
image sharp and in focus.
An image with a shallow or small depth of field will usually
have only a small part of the image sharp and in focus.
There are three things which can change the depth of field:
1. The aperture
2. The focal length of the lens used
3. How near the subject focussed on is to the camera

5. Depth of Field

6. Large depth of field = small apertureShallow depth of field = large aperture

7. Aperture & Depth of Field

11. The reciprocal relationship

12. Camera lens focussed on the barbed-wire Large aperture (f2)
Note how the background is out of focus.

13. Camera lens focussed on the barbed-wire Small aperture (f16).
Note how whilst not completely in-focus, the background is sharper
1. Changing the Aperture

14. Large aperture (f2.8) – Note how not all the seaweed is in focus

15. Small aperture (f22)

16. Two photographs from the same
position, both with the camera
focused on the wooden beams.
Which image was made using a
small aperture and which with a
large aperture?

17. Two photographs from the same
position, both with the camera
focussed on the wooden beams.
Which image was made using a
small aperture and which with a
large aperture?
Small aperture (f22)
Large aperture (f4)

18. Large aperture Small aperture
One of the problems with using a small aperture to get maximum depth
of field is that to get the correct exposure a much slower shutter speed
may be required. This has led to a problem in the right hand image …

19. Large aperture Small aperture
The right hand image was taken at a slow shutter speed (1/30) to get
correct exposure and because of this the moving fishing net has become
blurred (motion blur).

20. 1. Where was the camera focused for both images? 2.
Which image was made with a small aperture and which with a large aperture?

21. There are two other variables which also
alter the depth of field:
2. Focal length of lens
Long focal length lenses (telephoto lenses)
have less depth of field than short focal
length lenses (wide angle lenses).

22. F16, 1/250 of a second
24mm (wide angle) lens
F16, 1/250 of a second
100mm (telephoto) lens
(To take this picture I had to stand
much farther away from the car to
get a similar composition)

23. 3. Distance of subject to the camera
The nearer you are to the subject which you
focus on, the smaller the depth of field.

24. f5.6, 1/500 second
Camera close to car
f5.6, 1/500 second
Camera even further from
the car.
f5.6, 1/500 second
Camera further from
the car
Three images
taken with the
same lens and
exposure, each
focussed on the
car.

25. Using Depth Creatively

27. Aperture & Depth of Field

33. SUMMARY
Depth of field is affected by THREE factors:
1. The aperture (small apertures give more
depth of field)
2. The focal length of the lens (shorter focal
lengths give more depth of field)
3. The distance from the camera to the subject
focussed on (the greater the distance the
greater the depth of field).
Chris Monaghan

34. Create a new page in Pinterest
called ‘Depth of Field’
Collect examples of depth of field
Collect some examples show
large depth of field – where
things in the foreground and
background are in focus.
Collect some examples of
shallow depth of field –
where the things in the
background are not in focus.

35. Use the still life objects to set up a composition.
The zone of sharp focus is called the depth of field
• Show shallow depth of field (large aperture / small f stop number)
• Compare with extended depth of field (small aperture / large f stop number)