The document discusses how apertures work in cameras and affect photographs. It explains that apertures control both depth of field and the amount of light reaching the sensor. A large aperture gives a shallow depth of field while a small aperture gives a deep depth of field. Apertures are measured in f-stops, with smaller numbers representing larger apertures that allow more light. Understanding how to use different aperture and shutter speed combinations is key to great photography.

1. Controlling Your Camera
Apertures

2. Apertures have two effects on
your photographs:

3. Apertures have two effects on
your photographs:
They control the depth of field.

4. Apertures have two effects on
your photographs:
They control the depth of field.
And they control how much light
reaches your sensor.

5. The depth of field means how much of the
shot is in focus.

6. The depth of field means how much of the
shot is in focus.
A large aperture has a shallow depth of field
and a small aperture has a deep depth of
field.

7. So, what exactly is an aperture?

8. The aperture of your
camera is controlled
by a diaphragm that
opens and closes to
let in different
amounts of light.

9. The diaphragm
of your camera
works much like
the pupil of the QuickTime™ and a
decompressor
human eye,
are needed to see this picture.
opening and
closing to adjust
the amount of
light that
reaches the
eye.

10. It operates very
much like a leaf
shutter, but you
should not confuse
the two.

11. It operates very
much like a leaf
shutter, but you
should not confuse
the two.
Your camera has a
shutter and an
aperture diaphragm.

12. Camera
lenses may
have many
different
sizes of
apertures.

13. The diaphragm is
located inside
your lens and is
composed of
overlapping metal
leaves.

14. The diaphragm is
located inside your
lens and is
composed of
overlapping metal
leaves.
Its movable leaves
can be opened
wide to let in more
light or closed
down to let in less.

15. On early
cameras the
aperture was
adjusted by QuickTime™ and a
individual metal
decompressor
are needed to see this picture.
“stop” plates
that had holes
of different
diameters.

16. The term stop
is still used to
refer to the
aperture size,
and a lens is
QuickTime™ and a
decompressor
are needed to see this picture.
said to be
“stopped down”
when the size of
the aperture is
decreased.

17. There is a
standardized,
full-stop series
of numbers on
the f-stop scale
as shown here.

18. The smaller
numbers
correspond to
the larger
apertures, and
admit the most
light.

19. Each larger
numbered full f-stop
admits half the light
of the previous one.

20. Each larger
numbered full f-stop
admits half the light
of the previous one.
A lens that is set at
f/4 admits half as
much light as one
set at f/2.8.

21. Notice that f-stops have the same
half or double relationship that
full-stop shutter-speed settings do.
QuickTime™ and a
decompressor
are needed to see this picture.

24. Digital cameras usually
have more than just the
full stops available.

25. Here the
apertures
are full stops
and have a 2
to 1
relationship.

26. The hardest
thing to
remember
about
apertures is
that the higher
the number,
the smaller
the aperture.

27. The easiest way to
remember is to
equate the numbers
to the amount of the
scene that is in focus:
ie. f/2.8 (2.8 feet total
in focus) will have a
shallower depth of
field than f/22 (22
total feet in focus).

28. Depth of field
is the area
from near to
far in a scene
that is
acceptably
sharp in a
photograph.

29. As the aperture
changes, so does
the depth of field.

30. On this lens, there
is a depth-of-field
scale (many lenses
do not have one)
that you can use to
estimate the extent
of the depth of
field.

31. The bottom row
shows the aperture
(f-stop).
Here it is set at f/2.

32. The middle ring
shows the range of
focus for each f-
stop

33. And the upper ring
shows the actual
distance within which
the lens is focused.
The point of focus in
this depth of field is at
about 7 feet from the
camera lens.

36. Only the narrow section marked “b” is in focus.

37. Here the aperture is set to
f/16.
Looking at the guide, you
can see that the depth of
field at this aperture is from
about 5 feet to 13 feet from
the lens.
Everything between those
two points is in focus.

40. In this case, more of the scene is in focus.

41. Few lenses provide a range of
apertures greater than eight stops.
QuickTime™ and a
decompressor
are needed to see this picture.

42. Lenses are often described as
fast or slow.
QuickTime™ and a
decompressor
are needed to see this picture.

43. These terms refer to the width of the
maximum aperture for the lens.
QuickTime™ and a
decompressor
are needed to see this picture.

44. A lens that opens to f/1.4 opens wider
and is said to be faster than one that
opens only to f/2.
QuickTime™ and a
decompressor
are needed to see this picture.

45. Faster lenses allow you to shoot
more easily in low light or at faster
shutter speeds.
QuickTime™ and a
decompressor
are needed to see this picture.

46. Fast lenses are also more expensive
than slower lenses.
QuickTime™ and a
decompressor
are needed to see this picture.

47. The key to great photography
is learning how to use the
shutter and the aperture
together.

49. Each combination of aperture (f-stop) and shutter speed
gives you the same exposure.

50. Each combination of aperture (f-stop) and shutter speed
gives you the same exposure.
This means that each combination allows the same
amount of light to reach your camera’s sensor.

51. However, this does not mean that each
exposure makes the same photograph.
Remember that the aperture and
shutter speed affect the motion blur and
the depth of field.

52. In this example, a small aperture is used, so
a longer exposure time is required. This
longer shutter speed gives the photo some
motion blur. And the picture has a deep
depth of field.

53. Here the same shot has been exposed with a larger
aperture and a shorter shutter speed. Less of the
background is in focus because there is only a
moderate depth of field. But the quicker shutter
speed catches more of birds and less of the motion.

54. In this final exposure, the scene is captured with a
larger aperture and a very fast shutter speed. Thus
there is a very shallow depth of field (less of the shot
is in focus). But the fast shutter speed captures the
birds entirely without any motion blur.

55. What combination of aperture and shutter speed do
you guess was used here?

56. A small aperture to get the deep depth of field and a slow
shutter speed to capture the motion blur of the guy sweeping.

57. Paul Shambroom, B83 Nuclear Gravity Bombs in Weapons Storage
Area, Barksdale Air Force Base, Louisiana, 1995

58. Aperture and shutter speed?

59. Background in focus, so a small aperture, and also a fast
shutter speed because no motion blur. Bright daylight
made this combination possible.

60. Sebastiao Salgado, Gold Miners, Serra Pelada, Brazil, 1986

61. How do you think this photo was taken?

62. Camera is attached to one of the roller coaster cars and a
relatively slow shutter speed was used.

63. Robert Landau, Untitled, nd.

64. Aperture? Shutter speed?

65. Wide aperture, fast shutter speed.

66. Lou Jones, Women Swimming, 1998

67. Aperture? Shutter speed?

68. Probably a medium aperture and a faster shutter speed.

69. James Nachtwey, Nicaragua, 1982