How to Test For LED Flicker

The Importance of Flicker-Testing

In today’s lighting market, LED flicker has become a widespread issue. From workplace fatigue to migraines, the consequences of unchecked flicker deserve our attention.

Both the US Department of Energy and the State of California have released reports on the negative effects of LED flicker as well as systems to test and rate LED fixtures for existence of flicker.

This is a guide based on these observations and suggestions, so that you can test LED fixtures for flicker anywhere and easily with just your smartphone.

Smartphone Requirements

* Samsung Galaxy S7 and above

* iPhone 6 and above

Download A Printable Handout

Step 1. Enable 240 FPS (Frames Per Second)


  1. In the camera app, open settings (gear icon).
  2. Scroll down and select “Edit camera modes”.
  3. Select “Rear Camera”.
  4. Find “Slow motion”, tap to enable.


  1. On your home screen, open “Settings”.
  2. Scroll down and select “Camera”.
  3. Select “Record Slo-mo”.
  4. Confirm that the “240 fps” option is selected.

Step 2. Enable Slow Motion

In your Camera app, switch the mode to slow motion.

Android: "Slow Motion"


Step 3. Test for Strobing

To detect strobing, point your camera at the light source without recording.

Strobing will show thick dark lines slowly 'rolling' across the light fixture.

Step 4. Test for Shuttering

To detect shuttering, record the light source and review the footage.

Shuttering will show the light fixture turning on and off at a rapid pace.

What is LED Flicker?

LED Flicker is the repetitive change in magnitude over time, or modulation, of the luminous flux of an LED light source.

Though flicker is often invisible to the human eye, our neurons detect and respond to the sensation.

Potential Flicker-Induced Impairments:

  • Neurological problems, including epileptic seizure
  • Headaches, migraines, fatigue, blurred vision, eyestrain
  • Reduced visual task performance and distraction
  • Increased autistic behaviors, especially in children

Source: US Department of Energy (2015)

See Our Videos Demonstrating LED Flicker

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