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R5 weird "stuttering lines" shutter

Started 1 month ago | Discussions thread
Ephemeris
Ephemeris Senior Member • Posts: 1,186
Re: R5 weird "stuttering lines" shutter

charlyw64 wrote:

It seems you have a few misunderstandings of what happens with LED when they are dimmed. When dimmed the LED electronics shorten the pulses that the LED is driven. It no longer flickers with the mains frequency but rather a much higher frequency. You are using a slow shutter speed, that encompasses several full flicker cycles - so the anti flicker solution of the camera does nothing for you (it is a solution for shutter speeds faster than the flicker pulse length). The problem you see is due to subject movement during the exposure, you get the subject lit in different positions as the light goes through several pulses.

Who is this replying to sorry Charlyw?

My personal point (if it is relavant) is that at least some mains LED lamps capable of being dimmed are not driven at a mains multiple frequency when on an effective 100% duty.

If we monitor the current to the LED or LED array we will see this looks continuous unless we start to look at much shorter time windows.

If we look at some none dimmable we can see at the duty cycle we call ON, that the current is modulated with a frequency related to that of the mains current.

What then occurs optically is different due to the luminophore.

Quite a few articles on the effects of light Flickr on human health and also some regulations / guidance.

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