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Activity Forums DSLR Video Flickering LED Display! UGH!

  • Flickering LED Display! UGH!

    Posted by Lisa Hurley on August 24, 2020 at 4:55 pm

    Hello… I was hired to create a short ad for an Amazon listing….. the product is an automatic blood pressure device. The LED flickers excessively. I did some reading about this problem, and discovered that sometimes it can be fixed by changing the settings on the camera. Some of the information was a bit “over-my-head” so to speak.. because the article dealt with mathematics.. haha!

    I have created three clips that I tried using three different frame rates on my camera… which is a Canon 70D. I do not see any improvement in any of these….

    I am HOPING someone here may have some advice to get this flickering down to at least a minimum….. The client said that a little flicker will be okay.

    Thanks in advance!

    Lisa Hurley LINK to VIDEO:

    Wayne Williams replied 3 years, 8 months ago 3 Members · 2 Replies
  • 2 Replies
  • Blaise Douros

    August 25, 2020 at 10:35 pm

    If you’re working with the manufacturer, ask them what the refresh rate is for the LED. If they’re using Pulse Width Modulation to moderate the brightness, knowing the rate of the pulse will be important. PWM means that in order to modulate the apparent brightness, instead of reducing the voltage, the LED is pulsed on and off: so if they want 50% brightness, they pulse the LED so it’s only on 50% of the time, which our eyes read as dimmer.

    If they are using PWM, setting the screen to its highest brightness setting will probably help–sometimes that sets the LEDs to “always-on” instead of flickering at high speed.

    Ultimately, you’ll need to shoot in the correct delivery frame rate–but you can change your shutter speed to your heart’s content. A slower shutter is probably going to work better, in this instance. If you’re shooting at 1/50th shutter over 23.976 fps, try slowing the shutter down to something close to the framerate–1/30th or 1/24th if your camera will do that.

    Basically, what’s happening is that the LED is blinking at a different speed than the camera’s shutter, so each frame is capturing varying brightness levels across frames. Slowing the shutter down allows the camera to expose more evenly across frames.

  • Wayne Williams

    September 9, 2020 at 1:44 am

    helpful… thanx

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