Stingray taillights

[ICEYOU]

Why are they flickering?

 

[Slash]

I noticed that in other videos. Not sure why.

 

[Beeblebrox237]

I've seen that in many, many Top Gear reviews, and it's always puzzled me. Do they do something to the electronics of these cars?

 

[BobbyBRAKEaNek]

They're not flickering. It's the recording device.

 

[McLaren]

From the last thread that asked this question.

From my limited scientific knowledge

Most lights flash. We don't normally see it though as they're flahing very quickly and our eyes filter it out so we see a solid light. A camera, which catches single frames of time, can sometimes catch it when the light is "off", or refreshing, so it looks like it's flashing when viewed as a video. It's a similar thing to refresh rates on a monitor.

Probably...

Yes, this happens with LED lights. The older bulb lights are just being switched on or off and thus don't flash.

LED lights however are pulsed for a different brightness, so when filmed with a camera which captures discrete frames, these lights can flash because the camera catches them sometimes on and sometimes off, as daan explained. Example: you have one set of lights for driving and braking. When you do not brake, the LEDs are pulsed. This happens so quickly that the human eye can not distinguish the on-off-periods, so you just see a reduced brightness. When you brake and the lights come on, the LEDs are simply being tuned on all the time, so the light appears brighter to the eye.

 

[Doog]

It's the way the LEDs in the lights react with the camera for some reason. You'll notice the way Audi headlights are always flickering in videos.

Aand I'm tree'd.

 

[Slash]

^^I thought that too at first but I kept my mouth shut.

 

[ICEYOU]

They're not flickering. It's the recording device.

why are they flickering during recording though?

 

[McLaren]

why are they flickering during recording though?

The answer is above....

 

[NissanSkylineN1]

Its because LED lights flash on and off really fast, hence why they also save energy. Take an LED christmas light and move it fast side to side in front of you. You can see it will trail.

 

[Beeblebrox237]

Fascinating. Thanks for the information!

 

[ICEYOU]

Is it possible for the camcorder companies to fix this issue?!

 

[Jet Badger]

Ofcourse. Get a 1000 fps camera and after finishing recording simply delete the frames you don't like manualy

 

[Famine]

Is it possible for the camcorder companies to fix this issue?!

Sure. All they have to do is make cameras that record at either the same number of frames a second as the frequency of the electricity used. Which only means redefining world video standards or world electronics standards...

LEDs are solid state and they're only "on" when supplied with the correct current at the correct potential. They are supplied with 1.2V of electricity at 60Hz, so they're "on" 60 times a second, when the current and potential supplied passes the lower threshold required for them to be "on" and they're "off" 60 times a second when it drops below that limit.

Video cameras record at around 24 frames a second - one, single, still frame is captured every 1/24th of a second. Sometimes that frame will capture the LED in its off phase and, on average, that will happen [electricity frequency]/[frame rate] times a second, which here is 60/24 - or 2.5 times a second.


Why doesn't this happen with gas discharge and filament lights? It's because they both rely on a heating threshold, not a current one. As the electricity passes through the medium - gas or a solid tungsten filament - the medium heats up and emits light. The 1/60th second "off" phase doesn't give the medium sufficient time to cool down and stop emitting light, so they stay "on" to the point of view of the 24fps camera. Viewed close enough at a high enough frame rate, they'll appear to flicker too, albeit only in terms of light levels and never "off".

 

[Guardian]

This thread is awesome. The flickering lights have always puzzled me, ever since the TopGear 458 review. I just never got round to asking about it though. Now I can rest.