Non-Flickering LED Strip

[Ken Coker]

Comrades

 

I'm looking for LED strip that doesn't flicker/strobe when photographed or filmed. I already have some high-quality drivers and dimmers, so I need strip to match. 4000K colour temperature too.

 

Many thanks

 

KC

[DrV]

I'm not sure I can see how the strip itself would have any influence on the problem. LEDs simply respond instantly (near enough) to changes in current so you have to look at the drivers. If it's any help the City Theatrical D series dimmers have settings to alter the PWM rate so you can choose one which doesn't cause strobing with your particular frame rate.

Dave

[Ken Coker]

......(near enough)....

 

...indeed, however, the LED strip supplied to me is the very cheapest Disco Dave product that our friends in the east have yet made....

[GR1]

LED Ltd of Ashford Kent have supplied LED tape used in many UK TV studios. I've worked on many projects using their materials. They don't flicker at High Res when used with the correct drivers. I've never experienced the LED tape being a problem, it's usually the drivers but there's a first time for everything.If colour temperature control is vital use bi colour tape. The Warm White /Cool White mix will give the flexibility you need.

[timsabre]

Dave is right, it is the driver that determines the flicker so if you have high quality drivers then cheap tape is as good as any other.

 

(except for pixel tape, where each led does its own dimming)

[maeterlinck]

If the tape is flickering then there is a fault. Which drivers do you have? I'd suggest PWM frequency of >1kHz for 60fps.

 

What frame rate are you shooting at?

[Tomo]

"Pixel" LED tape has built-in drivers and many of those will flicker.

 

DC Constant Voltage and Constant Current LED tape/modules are never a source of flicker.

- CV are just a diode and a resistor, while CC are just a diode.

 

(Aside from failed diodes and bad joints/wiring)

 

Assuming your wiring is good and the LEDs are actually soldered to the tape, the LED driver and/or power supply are the sources of any and all flicker.

 

If you're seeing visible flicker, your drivers PWM is too slow for the camera (settings) you are using.

- If the flicker looks like horizontal "banding", then your camera is a "rolling shutter" type (these are extremely common) and needs a much higher PWM frequency than 'classic' shutters.

 

Some LED fixtures and drivers have an adjustable PWM frequency, however do note that increasing the PWM frequency reduces flicker but causes dimming to become more steppy. It's a fundamental tradeoff.