Sunny 16 Rule & Equivalent Exposures

FOUR FACTORS THAT CONTROL EXPOSURE

Aperture Size Shutter speed ISO setting Brightness of the scene

EXPOSURE

A combination of Aperture size and Shutter Speed control the amount of light entering the camera. Consider ISO the sensitivity of the camera’s sensor to accepting that light. How bright the scene is determines what settings (F-stop, Shutter Speed and ISO) need to be set on the camera so as not to make the final image too light or too dark.

DOUBLING VS. HALVING EXPOSURE F-Stop

1.4

2

2.8

4

5.6

8

11 16

Shutter Speed

1

2

4

8

15

30

60 125 250 500 1000

ISO 12800 6400 3200 1600 800 400 200 100

22 50

32 25

45 12

On the chart, to move from one number to the other is a stop. Adding one stop more exposure is doubling the exposure. To add one stop less exposure is halving the exposure. The camera’s sensor is getting half the light. To go from F5.6 to F4 is doubling the exposure (smaller number = bigger aperture diameter). To go from 15 (actual 1/15) to 30 (actual 1/30) of a second is halving the exposure (less time the shutter is open).

THE SUNNY 16 RULE

For the correct exposure on a Sunny Day: Set the F-Stop to 16 Set the shutter to 1/100 of a second (or 1/125) Set the ISO to 100

Exposure Chart in Full Stops F-Stop is the Camera’s Aperture Setting F-Stop

1.4

2

2.8

4

5.6

8

11 16

Shutter Speed

1

2

4

8

15

30

60 125 250 500 1000

ISO 12800 6400 3200 1600 800 400 200 100

22 50

32 25

45 12

Sunny 16 Settings

ISO Set to 100 1/125 F16

1/1000 F5.6

What is the equivalent exposure at F5.6 for the same ISO setting? F-Stop

1.4

2

2.8

4

5.6

8

11 16

Shutter Speed

1

2

4

8

15

30

60 125 250 500 1000

ISO 12800 6400 3200 1600 800 400 200 100 marks the current exposure settings

22 50

32 25

45 12

Moving to the left add a minus sign to it F-Stop

1.4

2

2.8

4

5.6

8

11 16

22

Shutter Speed

1

2

4

8

15

30

60 125

250 500 1000

ISO 12800 6400 3200 1600 800 400 200 100 Moving to the right add a plus sign to it

50

32

25

45

12

Add up the changes in exposure to equal zero The F-stop decreased in number so give that a -3 Therefore the Shutter speed has to be increased by 3 The equivalent exposure is F5.6 at 1/1000 of a second

Reduced depth of field at Equivalent exposure

F16@ 1/125 second

F5.6 @ 1/1000 second

Another example What if the ISO is changed from 100 to 25. What would the shutter be if the F-Stop is 5.6? F-Stop

1.4

2

2.8

Shutter Speed

1

2

4

4 5.6

8

11 16

8

30

60 125 250 500

15

ISO 12800 6400 3200 1600 800 400 200 100

ISO is moved two stops to the right (positive)

22 50

32 25

45 1000

12

Final Equivalent Exposure IS 1/250 second shutter speed at F5.6 and ISO 25

F-Stop

1.4

2

2.8

Shutter Speed

1

2

4

4 5.6

8

11 16

8

30

60 125 250 500

15

ISO 12800 6400 3200 1600 800 400 200 100

22 50

32 25

45 1000

12

To zero out the numbers, Shutter speed needs to go two stops to the left (negative) which would be 1/250.

Keeping Equivalent Exposure

Decreasing the sensitivity of the sensor 2 stops the camera’s shutter needed to stay open longer by 2 stops. Rule: Using Exposure chart, adding changes in ISO, Shutter Speed and F-stop must equal zero. Your camera automatically does this on Program mode.