Home Open Account Help 245 users online

Model Railroading > LED Headlights Flash When Videoed


Date: 09/14/22 19:15
LED Headlights Flash When Videoed
Author: just4frost

A friend takes videos of my trains down at the local hobby shop layout, and he then posts them on YouTube.  The headlights on LED equipped locomotives show up as a steady, rapid flashing when viewed on YouTube. They do not flash when viewed in person. Headlights with incandescent bulbs do not flash when viewed on YouTube, only LED's. His phone is a recent issue iPhone, but I am not sure the model number. Again,  no flashing is evident when viewing the locomotives in person. Any ideas what could be the cause of this flashing effect, and how it can be corrected?

Thanks for any suggestions.

Warren



Date: 09/14/22 19:47
Re: LED Headlights Flash When Videoed
Author: KM-ML4000

The camera sensors capture video images, or samples, at nearly the same rate as the modern DCC decoders drive the LEDs through pulses known as Pulse Width Modulation (PWM). This makes LEDs appear to be flashing when captured on digital video.



Date: 09/14/22 20:07
Re: LED Headlights Flash When Videoed
Author: just4frost

Thanks. So, there's no fix?



Date: 09/14/22 20:33
Re: LED Headlights Flash When Videoed
Author: Lurch_in_ABQ

The LEDs are in fact blinking. The human eye can't keep up with the LED blink rate so the LED appears steady on.
  
"...The human eye and brain can only process about 12 separate images per second, retaining an image for 1/16 of a second. If a subsequent image is replaced during this time frame, an illusion of continuity is created..."
  

What is Persistence of Vision? Definition of an Optical Phenomenon (studiobinder.com)
"...The human eye and brain can only process about 12 separate images per second, retaining an image for 1/16 of a second. If a subsequent image is replaced during this time frame, an illusion of continuity is created...." 
 



Date: 09/14/22 21:12
Re: LED Headlights Flash When Videoed
Author: KA7008

Change the fps rate if you can.  I can't recall the details but it's an issue with frames per second that causes this.



Date: 09/14/22 21:14
Re: LED Headlights Flash When Videoed
Author: JETRR

Adjust your video camera's FPS (frames per second) if your camera has that feature. 



Date: 09/15/22 08:47
Re: LED Headlights Flash When Videoed
Author: pullmanboss

I've taken to watching cab ride videos from Europe and the UK on Youtube when I want something interesting yet mindless to watch, and the LED trackside signals always blink. 



Date: 09/15/22 14:12
Re: LED Headlights Flash When Videoed
Author: Bscale316

Same thing happens with car review videos.
Makes it look like the emergency flashers are on.
Bill in Ft Worth



Date: 09/17/22 09:54
Re: LED Headlights Flash When Videoed
Author: toledopatch

The LED headlights on 1:1 scale locomotives also flicker at a rate so fast your eye won't see it, but a camera shooting frames at 1/500 of a second will. Oftentimes the individual diodes are flashing out-of-sync, so in a still frame it will look like some of them were lit while others weren't at any given moment.



[ Share Thread on Facebook ] [ Search ] [ Start a New Thread ] [ Back to Thread List ] [ <Newer ] [ Older> ] 
Page created in 0.04 seconds