I have a question, I have noticed that when videos of LED lights are filmed the lights seem to be flickering but they are not to the naked eye. Can this be due to the half bridge rectifier they are using to convert AC to DC?
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I don't think so, you see the same flicker in videos of cars with LEDs, and they're dc systems
Just blink your eyes at the same rate so you'll see a constant light 
I don't see the flickering of LED's on camera when they're powered using DC or AC on the bench. I suspect the flickering is due to PWM modulation to control brightness.
Here's two videos, they're processing now. One is shot with the Samsung Note 2 cell phone camera, the second with a Panasonic Lumex camera.
I've noticed at night if you look at car taillights that are LEDs that if you turn your head quickly you see a string of multiple lights, probably do flicker at some rate but have no idea the specifics.
However these folks do...
Jerry
I just recently watched two videos where it was noticeable. One was a layout video on the forum here and the owner mentioned it. The other was Eric's review of the
Lionel FM H24-66 TrainMaster Diesel https://www.youtube.com/watch?v=l0SZnH8vm4Y
Thanks for the input.
I've noticed flickering on video's particularly from MTH locomotives with PS-3 using LED's in those engines now.
I provide video surveillance cameras and systems to banks for a living and when recording, the cameras are actually recording individual images, similar to film, at varying rates of anywhere from 1 to 32 frames per second. I suspect the flickering has to do with the recording rate as well as compression algorithm that was used.
Here is the other video, it is Spence's layout, it is about halfway through, when he loers the lights, it becomes visible. http://spencerstrains.webs.com...1884-my-layout-video
It's the moth effect when it comes to illumination and sparkling things we humans see what we want to see and become as moths to a flame. There was a thread earlier in the week about this phenomenon.
xrayvizhen and baltimoretrainworks have the answer. The flicker you see in the videos is the result of the camera's image captue frame rate and the flicker of some Led's. Sometimes the two sync in just the right way that the camera starts capturing the flicker our eyes don't naturally see because it happens so fast.
Originally Posted by abbrail:
xrayvizhen and baltimoretrainworks have the answer. The flicker you see in the videos is the result of the camera's image captue frame rate and the flicker of some Led's. Sometimes the two sync in just the right way that the camera starts capturing the flicker our eyes don't naturally see because it happens so fast.
It's not just LED's. I've mounted a camera on the dashboard of a Cessna 172 and depending on the the camera, the propeller, spinning anywhere from 1500 - 2400 RPM, will appear to be either stopped, or spinning slowly both clockwise and counterclockwise.
It's essentially a strobe effect.
The late Catherine Crozier, concert organist, told of a sales rep for an early electronic instrument bragging that their organ had such a broad frequency range, that it extended beyond the range of human hearing...... 
Originally Posted by Chris Lonero:
I've noticed flickering on video's particularly from MTH locomotives with PS-3 using LED's in those engines now.
PS3 uses PWM to drive the LED's. so you could witness flickering due to that.
Gunrunner John, Thank you. It seems that it may be a cross between PWM and the frame rate from what I have gathered here. It was just interesting that I have noticed it with both Lionel and MTH when filmed. Just one of those audities that gets under my skin until I get it figured out.
I suspect Lionel may be using PWM for the LED's on the newer Legacy stuff, I haven't actually slapped a 'scope on them to see.
