WIKI-2C

Light Ratios

Getting Started

• The study of light ratios begins with understanding how to use f-stop, shutter speed, and ISO.
• F-stop represents the quantity of light reaching the sensor based on shutter speed and ISO.

F-Stops

• Moving to a larger lens opening (whole stop) doubles the amount of light reaching the sensor.
  • Example: F16 to F11 doubles the light.
• Moving to a smaller lens opening (whole stop) halves the amount of light reaching the sensor.
  • Example: F11 to F16 halves the light.
• Exposure change through f-stops (and shutter speeds) is exponential, not linear.

Examples of F-Stop Changes

• F16 to F11: 2X the light
• F16 to F8: 4X the light
• F16 to F5.6: 8X the light
• F16 to F4: 16X the light
• F16 to F2.8: 32X the light

Light Increase with Opening the Lens

• 1 stop = 2X
• 2 stops = 4X
• 3 stops = 8X
• 4 stops = 16X
• 5 stops = 32X
• 6 stops = 64X
• 7 stops = 128X
• 8 stops = 256X

Light Decrease with Closing the Lens

• 1 stop = $$\