Module 2H-PPT

Module 2H:

Why Use Off-Camera Flash?

• Utilizing an off-camera flash outdoors and on-location gives the photographer significant control over lighting.

  • Control over the quality of light.

  • Control over the direction of light.

  • Control over the lightness or darkness of backgrounds.

  • Control over the quantity of light.

Larger Light Sources Provide Softer Light

• Getting the flash off-camera allows the use of various lighting modifiers like umbrellas and softboxes, which enlarge the light source and soften the light.

Directional Light

• Moving the flash off-camera allows for desirable directional lighting patterns.

• Additional flashes can be used for fill, hair, background, and kicker lights.

Consistent Exposures

• Off-camera flash allows photographers to move freely without changing exposure settings based on camera-to-subject distance.

• When the flash is on a stand, its position is fixed relative to the subject, regardless of camera movement.

Advantages of Monolights

• Speedlights can be used off-camera with adapters and remote triggers.

• Battery-powered monolights are designed for use with light stands.

• Monolights often have built-in radio receivers that work with a transmitter on the camera.

• Transmitters can control the light output remotely, even controlling multiple monolights simultaneously.

Determining Exposure

• Many factors affect the amount of light on the subject when using off-camera flash:

  • Flash power.

  • Flash zoom head position.

  • Flash output settings.

  • Flash-to-subject distance.

  • ISO value.

  • Lighting modifiers.

• The most reliable way to determine exposure is to use an incident light meter.

• Take a test exposure with the meter at the subject position to find the resulting f-stop.

Lowering the Output of a Portable Flash

• Speedlights and monolights can have their output powered down, similar to a dimmer switch.

• Some flashes adjust in one-stop intervals, while others use 1/3 or 1/10 stop intervals.

• Many speedlights use ratio values to indicate light output.

Power Ratios and Stops

• 1/1 = Full Power output of the flash

• 1/2 power reduces the output by 1 stop

• 1/4 power reduces the output by 2 stops

• 1/8 power reduces the output by 3 stops

• 1/16 power reduces the output by 4 stops

• 1/32 power reduces the output by 5 stops

• 1/64 power reduces the output by 6 stops

• 1/128 power reduces the output by 7 stops

Simplified Power Down Versions

• Some speedlight brands and most monolights offer a simplified version for powering down the flash:
  9 = Full Power output of the flash
  8 = reduces the output by 1 stop
  7 = reduces the output by 2 stops
  6 = reduces the output by 3 stops
  5 = reduces the output by 4 stops
  4 = reduces the output by 5 stops

Flash to Ambient Balance

• Example:

  • Ambient exposure: f/8 at 1/125.

  • Meter reading from flash: f/11 at power level 8 (monolight).

  • Equivalent speedlight setting: 1/2 power.

• Adjusting monolight power output down to 7 results in a two-stop reduction from full power (1/4 power on a speedlight).

• After adjustment, the meter reading for the flash was f/8, matching the camera's working f-stop.

Flash and Ambient Light

• When the background is brighter than the ambient light on the subject, flash can balance the exposure.

• When the exposure on the subject is about the same as the exposure of the background, the image looks balanced.

Adding flash

• Image taken with an off-camera flash to camera left, set one stop less than ambient light (f/2.8).

• Creates a directional light pattern with subtle highlights and shadows without an obvious flash effect.

Flash Meters

• A flash meter can aid in setting the flash to achieve desired results.

• The percentage readout compares the flash output to the ambient light.

  • 50% means ambient and flash are equal.

  • Below 50% means ambient light is dominant.

  • Above 50% means flash is dominant.

• Adjusting flash output to 50-75% is a good range for natural-looking images.