At plane sight, LED bulbs look stable to our eyes, but the only reason we perceive them to be stable is that LED light sources flicker at a rate imperceptible to the human eyes.
You may have observed an LED bulb making a flickering image in your camera, but running normally when viewed directly, this also happens with cars that have daytime lights, directing a smartphone camera towards the light source will reveal this strange phenomenon.
So, Why Do LED Lights Flicker On Video & Camera?
LED lights flicker on video because the frames per second (FPS) recording of the camera is not aligned with the frequency of electricity. This phenomenon is known as the ‘strobe effect’. LED lights are of two types i.e. strobe and constant.
LED lights flicker at rates that are imperceptible to the human eye. As a hobbyist automotive journalist, I’ve come across multiple photographers tugging out their hair in annoyance when a car’s lights appear to flicker.
Back in the day, when I started with my first camera, I would tug out my hair in annoyance when a car’s lights appeared to flicker. Little did I know that LED lights flicker at rates that are imperceptible to the human eye.
However, I was determined to find answers just like you, and that’s what we’ll be discussing in subsequent sections of this blog post.
What is the Strobe effect?
Try flipping through the pages of a book, you’ll notice that you can recollect the information on previous pages. This phenomenon is a human tendency known as “persistence of vision”. We can continuously perceive things even when they cease to be in front of us. This is why we perceive events as continuous and not a set of discrete still-shot images.
LEDs turn on and off at a very high frequency that is imperceptible to the human eye. Due to this, we see lights as being ON, until the light source is turned off.
LEDs flicker at a blistering rate, so fast that the flicker is imperceptible to the human eye.
Videos work the same way too, the images in a video are captured at a blistering rate measured in frames per second or FPS. When a video is played, our persistence of vision kicks in, tricking our brains into perceiving the series of images as one continuous fluid motion.
Flickering occurs when the FPS exceeds the frequency switching, you will observe this phenomenon on screen as an apparent malfunction. This is known as the strobe effect.
What is flickering?
Flickering is defined as a rapid change of an LED between its on and off states. The nature of the current supplied to an LED determines whether or not it will flicker.
When an LED flickers, it does so at a blistering rate, usually imperceptible to the human eyes. So you should know that any LED light flickering visible on a camera is normal.
Blinking of any sort should not be a concern unless it is visible to the naked eyes. Even so, it is not entirely true to say that LEDs flicker all the time.
Direct current (DC) supply
A direct current LED powered by a battery will always remain energized, since the electrons in the diode are always charged. due to the constant supply of electricity, they maintain a steady release of light energy and stay switched on, until the flow of current is interrupted. An LED powered by a DC source will not flicker on camera.
Alternating current (AC) supply
An alternating current works in a different way, unlike a direct current, an alternating current switches on two times and off 3 times in one cycle. which means, the charged electrons return to their shells 3 times by expending all their energy as light, only to be energized again. Because of the breaks in energy states, an LED powered by an alternating current would appear to flicker in a video.
Directly connecting an LED to alternating currents reduces their life dramatically due to cycling between states. To connect an LED to an alternating current, we must use regulators also known as ‘drivers’, which convert AC to DC, before supplying current to the LED light. When an LED is working through a driver, the flickering effect ceases to exist.
Pulse width modulation (PWM)
Some LED light circuits are designed to be smart, so we cannot entirely attribute the flickering of LED lights to AC or DC power supply.
LED lights powered by drivers may exhibit flickering to reduce power consumption. Instead of a continuous power supply, the power supply can be bundled into discrete pulses.
This will produce flickering similar to that observed in alternating current. This phenomenon is known as pulse width modulation. Pulse width modulation makes is the technology used in automotive daytime running lights and dimming lights.
Can flickering be stopped?
Stopping the flickering in itself is not enough, what are can eliminate is the irritating strobe effect.
Eliminating the strobe effect is a game of precision. One way to go about this is to adjust your camera’s frame rate and shutter speed to multiples of the frequency of the AC supply.
Besides the United States, in other parts of the world, alternating current is supplied at the rate of 50 Hz, meaning, the switching state between on and off cycles will occur 50 times in one second.
While adjusting the camera parameters, namely shutter speed and frame rate to values that are multiples or fractions of 50, can help to drastically reduce the strobe effect, there are other ways to tackle the phenomenon.
There are LED drivers capable of eliminating the strobe effect on their own. They do this by adjusting their flickering rate to exceed the frame rate of the camera, which results in the elimination of the strobe effect.
How to Stop LED from Flickering on Camera?
Camera setting
In today’s cameras, the functioning of the diaphragm holds the key to understanding why the flickering effect is generated. Modern lenses keep their diaphragm open at all times, the closure is only simulated electronically to calculate exposure.
When recording, the camera raises the mirror. Simultaneously, it closes the diaphragm to the set value, and everything goes back to the starting point after the recording.
The closing of the diaphragm while shooting does not happen precisely, both in terms of timing and size, which is why there’s a slight difference in exposure between two successive shots. One way to avoid this problem is by adjusting your frame rate to capture 25 images or less per second to avoid this problem.
As discussed earlier, the other factor that generates flickering comes from the way the sequence of photos for the video is exposed. This can be controlled by adjusting the shutter speed.
Remember, adjusting the shutter speed so that this is a multiple of 50 or 60, depends on where you are recording from. If you live in the United States, you should set it to a multiple of 60. A multiple of 50 will suffice in other parts of the world, this could be 1/50, or 1/100, of a second.
The reason why this eliminates flickering is the difference in the Hertz frequency of the current.
Using flicker-free LED video lights
While adjusting your camera settings work to eliminate the strobe effect, a more robust solution is to use LED lights designed for slow-motion filming. These LED lights are designed to get rid of the strobe effect.
In the photography, cinematography, and television industries, LEDs play a huge role, they have successfully replaced fluorescent lamps, thanks to their low energy consumption and low heat emission. However, they do flicker and that’s no longer a problem.
The advent of flicker-free LED lights on the market was a game-changer because they are compatible with a wide range of cameras on the market. These bulbs are available for both industrial and personal use.
The secret behind flicker-free LED lights is their ability to constantly regulate the power of the device, above all, it ensures the no-fade power of the LED.
If you find yourself filming regularly, then it’s time to invest in some flicker-free LED lights. These bulbs will help you eliminate the problems faced with standard lamps, and in the long run, they’ll be well worth the investment.
Getting rid of the flicker means more time to focus on content quality.
Using sunlight
Nothing beats nature, the easiest way to eliminate flickering or strobe is to film in the daytime. When I say daytime, I’m referring to the use of sunlight as a source of light.
Flicking occurs with fluorescent and incandescent light sources, but sunlight produced no flicker.
While sunlight remains the best option when you want to eliminate flickering, some factors can affect video quality output. For instance, low clouds may quickly cover the shooting area, in such a situation, you can adjust your camera setting as previously mentioned.
There are also times when you have to fix a flicker on legacy cameras because some of these old action cameras did not feature complete menu settings.
You can also use reflectors and diffusers with natural light. Also keep in mind, that the best time to record your video is early in the morning and around 5 PM. However, location and temperatures may affect suitable times.
Reposition Further Away from the Light Source
Increasing the distance between the light source and your camera is another way to reduce flickering. The reflective effect of light on your video will be lesser when you move further away from the light source. However, keep in mind that the frame will lose brightness as you move away from the source of light, So be sure to adjust the setting of your aperture and your exposure until you find what works best.
Use a Flicker Removal Plugin
Software like Adobe Premiere Pro has features that you can use to get rid of flickering. There are other programs, such as Flicker Free and more. Both Adobe Premiere Pro and Flicker Free will work well so long as you wait until the editing phase to remove the flickering.
A simple checklist to help you fix LED light flickering
Here are some useful tips to avoid or instantly fix the flickering problem:
- The flicker disappears if you power a lamp using a battery.
- Avoid using slow the slow-motion feature at night. If you plan to apply slow motion to a recording, do that during the day or apply a slow-motion effect in post-production.
- IF you still can’t get rid of the flicker, try adjusting the ISO. Modern cameras allow you to vary the sensitivity between shots.
- Cover your camera when not in use. This will protect it from rain or water.
How to remove LED light flicker from video
If you think about it, removing the flickering is easy. Simply correct the brightness value of each frame. That is, bring it back to a consistent value with the previous and subsequent frames. Luckily, special programs can do this maddening work for you. This is the so-called Post-production phase.
Post-production software has become more popular due to increasing technological demands. For example, removing flickering during the editing phase of production. This will have been impossible if not for special programs such as Adobe Premiere Pro or Elements, Final Cut Pro X, Corel VideoStudio, and more.
Post-production software includes Final cut pro, Adobe Premiere Pro or Elements, Final Cut Pro X, Corel VideoStudio, and more. In effect, video editing is a profitable business that offers you many choices.
While these programs allow us to manipulate or finetune recordings to suit our needs, they do come at a price tag and require specific skill sets to apply any effects. Mostly, technical skills coupled with the right plugin and tools.
These programs can create custom profiles that let you adjust varying details. For example, exposure, saturation, and brightness. This is why they have grown in popularity over the years and most video editors can’t go a day without their awesomeness.
If you are on a budget or cannot take out some time to acquire the necessary skills required to use any of the programs mentioned above, consider hiring an expert to get the job done.
Do incandescent bulbs also flicker?
Incandescent bulbs also turn off and on if they are supplied with alternating current. But unlike LEDs, the filament within the bulb does not cool down sufficiently during the ‘off’ state to show in any significant way on camera.
The flicker frequency is generally equal to the mains frequency (usually 50 or 60 Hz) or doubles that.
Because the alternating current varies its direction of flow continuously, polarity changes. Therefore, in each cycle, a maximum positive and negative value affects the bulb.
In reality, incandescent bulbs do flicker. They just do it much more slowly to voltage variations. When compared to fluorescent lamps, there is less noticeable flickering. However, this is not to say there is no strobing, your video will still display strobing.
Small light bulbs tend to cause flickering more than lights over 1Kw, Especially 100 Watt or smaller home bulbs.
If you’re experiencing issues with incandescent bulbs, now may be a good time to experiment with positioning the incandescent bulbs in different spots. You can add more bulbs, and change their angles, which would help to reduce the visual effect.
Conclusion
LED lights have changed the way photographers capture images. They give you a more natural-looking light and can produce stunning images.
So, when next you’re caught in a situation with LED flickering, you won’t fiddle with their housing in frustration. They are working just the way they are supposed to operate. After all, why repair something that’s not broken in the first place!
Sadly, they are not perfect on camera as they tend to flicker when they’re turned on or off, which is a cause of concern to photographers who need consistent lighting conditions.
But the good news is…
You don’t have to live with those horrible recordings, you can try out all those above-mentioned techniques to reduce LED flickers caught on our videos.
If you still can’t get rid of the flickering, then you should consider replacing your lighting because it might have an actual blinking problem that causes it to malfunction.
Now, I want to know your thoughts and experiences with LED flickering on video or camera:
- Do you have any other tips on how to fix LED flicker on camera?
Let us know your thoughts in the comments section below!
FAQs
Are flickering LED lights dangerous?
LEDs lights flicker at a rate imperceptible to the human eye. However, dogs can see these flickers.
While researchers are still studying this subject, these are some of the problems associated with LED flickering, they include:
- headaches
- eye fatigue
- malaise
- visual impairment
- epileptic seizures in screened subjects
To mention a few LED light applications, think of pc monitors, televisions, lighting panels, projectors, etc.
Since LED lights vary in sensitivity and frequency, these disturbances can lead to health problems down the line. While high frequencies are safe for humans, those below 120 Hz do.
In addition, Flickering LED lights can be distracting and uncomfortable. This takes a toll on your peripheral vision, as it is here that all movements appear more intense. Regardless of whether they are flickers or moving objects.
Underlying health conditions linked with eye health and irritability of the retina may worsen depending on the lighting conditions at that moment.
Your sensitivity might react around frequencies of 10 Hz and up. Generally, above 70 Hz, people hardly notice anything.
How do we know the LED light is flicker-free?
The naked eyes of humans cannot detect instabilities in light or flicker up to about 80 times per second. To detect flickering, we need a Flickermeter. This is just a piece of special equipment that can detect if a lighting source creates flickering.
You might have tried to search for apps that can do the same. But by and large, these apps cannot detect or gather technical data. Mostly, they try to make use of built-in mobile phone light sensors. As such, they lack reliability and accuracy.
You may have installed an app in a bid to detect flickering from a light source. these apps cannot detect or gather technical data. This is because they rely on built-in mobile phone light sensors, which are unreliable and inaccurate.
Standard flicker-free LED lights ship with a certificate of authenticity. In reality, eye comfort certification can take different forms in various nations. If you peruse the label or specs, you may find terms such as “flicker fusion rate or threshold”.
The leading independent security organizations prefer to use the term “flicker-free” to assign the related certificate. However, you’ll still find others who use the acronym OLED. The latter refers to an Eye Comfort Display certificate for low blue light and flicker-free emission.
If the package does not specify any related information and you do not have a flicker meter at your disposal, there’s no way to be sure. However, a high color rendering index (CRI) may also be useful to make a good purchase. A value greater than 80, is an indication that the color rendering is similar to that of sunlight.