Exploring the concepts and settings that allow cameras to control light when creating photographs.

1. M R . B E R D I N K A
DIGITAL PHOTOGRAPHY
TECHNOLOGY EDUCATION
DEPARTMENT
NORTHERN LEBANON HIGH SCHOOL
Exposure
How an image is produced

2. What is exposure?
 An image = single exposure
 The amount of light allowed to
reach the sensitized surface
 Overall brightness or darkness
 Too much light = overexposure
 Too little light = underexposure

3. Exposure – When you need a tripod

4. The “Histogram” – Light Analysis

5. How is the exposure controlled?
 ISO speed – determines sensor sensitivity
 Camera Exposure Settings:
 F/Stop – adjustable opening in the lens
 F/2.8, F/4.0, F/8.0, etc.
 Shutter Speed – gate the opens and closes
 ¼ sec, 1/60 sec, 1/500 sec, 1/4000 sec
 Filters – influences light entering the lens

6. Same Exposure – Different Combinations

7. Exposure settings the camera will use depend on:
 Shooting Mode
 Light source type
 Light intensity from source
 Sensor Sensitivity – ISO Speed
 Direction facing
 User adjustments

8. Same Light – Different Shutter Speeds

9. The Lens Aperture
 The lens has an opening called the aperture
 The opening size is measured in F/Stops
 Larger opening allow more light through
 Smaller opening allows less light through

10. Aperture
 Aperture
Actual opening in the lens
Size is known as the F-Stop of the lens
Low F-Stop = large opening (F2.8)
High F-Stop = small opening (F22)

11. Same Exposure – Different Settings
 How exposure (F/Stop) impacts clarity

12. The Shutter
 A plastic curtain like mechanism
 Moves up to open allowing light through to the image sensor
 The shutter opens for a period of time
 Short shutter allow s less light through
 1/1000 sec
 Long shutter allows more light through
 ¼ sec

13. Shutter Control
Shutter Speed
Opening in the back of the camera
Opening for a period of time
Fast Opening – 1/4000 sec (short amount
of time)
Slow opening – ¼ sec (long amount of
time)

14. Same Exposure - Different Settings
 How exposure (Shutter Speed) impacts motion

15. Using ISO to adjust exposure

16. When is the exposure correct?
 Depends on the subject content in the image
 The subject should always be the most important area of the
image when determining proper exposure
 Not all pictures can be properly exposed throughout
the entire image
 Get images as good as they can be
 Worry about the important areas first
 Take several at various exposures and see what
works best for that image
 Bracketing (+2, +1, 0, -1, -2)

17. Which exposure is correct?

18. Where is the Correct Exposure?

19. What happens when exposure is wrong?
 The image produced is either too bright or too
dark
 Images can be partially properly exposed in complex light
conditions (Ex. Strong back-lit condition)
 Overexposure
 Image is too bright overall
 Causes for loss of fine detail in highlights
 Colors appear faded
 Underexposure
 Image is too dark overall
 Causes for loss of detail in shadows
 Color appear muddy

20. Using the Histogram
 Using the Histogram to determine correct exposure

21. The light meter and exposure
 Camera uses the light meter to determine exposure
settings (F/Stop and Shutter Speed)

22. Using “Stops” to make an adjustment
 The camera’s base exposure is the “0” exposure
 “0” exposure is what the camera thinks is correct
 Adjustments are +/- stops of exposure
 Usually changed in 1/3 of a stop +/-

23. The Camera Screen

24. Creating Proper Exposure
 Allows for:
 Precise Detail
 Accurate Tones
 Vibrant Colors
 Good Contrast

25. Difficult Situations for Cameras
Times when the camera will get it wrong – Always!!
 The Moon
 Silhouettes
 Wedding Dresses (mostly white objects in dark areas)
 Night-Scapes

26. Some conditions are tricky
• Dark colored subject on a light background - usually comes out underexposed

27. At times the camera can get confused
• Light colored subject on a dark background – usually comes out overexposed

28. Calculating Shutter Speed
1/60 Shutter Speed: ____

29. Exposure

30. When the exposure goes wrong - Overexposure

31. Can produce excessive shadows

32. Broken Lighting leading to Overexposure

33. How is this Exposure?

34. What is Exposure Compensation
 Exposure compensation is a Manual adjustment to
the camera’s settings
 There are times when the camera is confused as to
what exposure will produce the best exposure
 Exposure is referred to in “Stops”
 Typical range is -2 - 0 - +2 (5 images total)

35. Where in the image should you be most
concerned about the exposure?
 Answer: the Subject
 You can help eliminate some common problems by
doing the following:
 Do no face toward bright lights or elements that cause glare
 Underexpose scenes that have a light colored subject
 Overexpose scenes that have a dark colored subject
 Zoom in so the subject occupies 2/3 of the image frame
 Take to a higher Point of View to reduce bright backgrounds
 Use low power flash to help eliminate shadows

36. What do you want you image to look like?
 Identify your priorities:
 Freeze motion - everything clear
 Motion Blur - objects moving allowed to blur
 Narrow Depth of Field – one object clear
 Wide Depth of Field – entire range clear
 Select a Shooting Mode that control what is needed
 If the settings you want to use don’t work, add:
 Tripod to hold camera steady (1/60 or slower)
 Filter to lens to reduce amount of light
 Additional Lighting to increase the reflection/intensity

37. Exposure Variables
 There are several different combinations that can
create proper exposure
 See the chart with Full Stops and 1/3 Stops to
calculate comparable exposure values
 Each full stop change is a double/half amount of incoming
light

38. Similar Exposure – Different Combinations

39. Exposure: F/14 * 1/500 sec. * ISO-400

40. Enlarged (F/14 – 1/500 sec – ISO 400)

41. Fast Exposure
 F/7.2 * 1/800 sec. * ISO-100

42. Really Fast Exposure
 F/5.4 * 1/4000 sec. *
ISO-200

43. Long Exposure Example
 Aperture F/16 Shutter Speed 25sec. ISO-100

44. Long Exposure Example
 Aperture - F/11 Shutter Speed 120sec. ISO-140

45. Really Long Exposure Example

46. Comparing Exposures

47. Shooting Modes
 P – Program
 Camera Selects both Aperture and Shutter Speed
 Manual adjustment using “Exposure Compensation”
 A – Aperture Priority
 Operator selects the aperture
 Camera selects the shutter speed
 Manual adjustment using “Exposure Compensation”
 S – Shutter Priority
 Operator selects the shutter speed, camera selects the aperture
 Manual adjustment using “Exposure Compensation”
 M – Manual
 Operator selects both aperture and shutter speed

48. Controlling light Using Manual Mode
F-Stop
(aperture)
Shutter Speed
Light meter
for exposure

49. Depth of Field Control – “A” Shooting Mode
F8.0 F5.6 F2.8

50. Advantages of a Narrow Depth of Field

51. Shutter Control – “S” Shooing Mode
 At times, you will need to use settings to simply control the
exposure
 Other times you will want to use certain settings to control
other attributes including depth of field or motion

52. Full Exposure Control – “M” Shooting Mode
 F/11 * 1.0 sec * ISO-160

53. Full Exposure Control – “M” Shooting Mode
 F/1.8 * 1/8000 sec *
ISO-320

54. What exposure controls would you guess?

55. What exposure controls would you guess?

56. HDR Photography

57. HDR Sample

58. HDR Sample

59. HDR Sample

60. HDR Sample

61. Sample

62. HDR Sample

63. HDR Sample