title- everything about smartphone camera flash

Everything About Smartphone Camera Flash

All of us take photos with our phones. Some perhaps more than others. Now and then, we’ve all been in a situation where the lighting for the photo is not ideal, and so we turn to the quickest and easiest solution-- the camera’s flash.

However, not many of us know just how a smartphone camera’s flash works, when to use it, and how to avoid some of the problems associated with mobile camera flash.

For example, how do you avoid the bluish tint some flashes leave on your pictures? And the red eyes in your photos? What causes that? Could the flash on smartphone cameras actually be harmful to our eyes?.

In this article, we will look at everything that you need to know about mobile camera flash.

Let’s start with…

Types of mobile camera flash

There are two different types of flash that you can find on smartphone cameras-- LED flash and xenon flash. Both have advantages and disadvantages that affect the quality of your low-light pictures.

Knowing which type your camera has and how it works will help you know what to expect from your smartphone’s camera when taking photographs in low-light conditions using flash.

LED flash

LED flash is the most popular type of flash found on mobile cameras that uses LED lights to illuminate a scene. It’s ideal because of its small size and energy efficiency, which fits perfectly with the size and design of smartphone cameras.

LED flash also comes in various forms such as single-LED flash, dual-LED, etc.

How LED flash works

An LED (light-emitting diode) is a semiconductor device that has two parts. One half carries positively charged material called P-Type (aka Holes). The other half carries negatively charged material called N-Type (aka Electrons).

Together, these two elements make up a diode. When a current is supplied to the diode, the negatively charged Electrons (N-Type) move in one direction while the positively charged Holes (P-Type) move in the other direction. Eventually, the two elements combine.

how an LED light works

When this happens, the electrons give off energy in the form of light. And thus the diode emits light, hence the name. Whether it’s a single-, dual-, or quad-LED flash, the principles of how the LED produces light are the same. The difference is the number of LEDs, their colour temperature, and their intensity.

Whether the flash goes off or not is controlled in the camera app. If the flash is deactivated on the camera app, there will be no current sent to the diode for it to emit light. So, there will be no flash. You will have to rely on natural or other types of artificial light to brighten up your photos, which is honestly better than using flash.

If the flash is activated in the app, a current will be released to the LED and it will light up. If you set the flash to auto-flash, the camera will analyse the scene and determine if it requires additional lighting or not. If it does, the flash will be activated.

Depending on the phone, the flash might go off in one or two stages. The first stage is usually a continuous light that lights up the scene so that the camera can see and adjust the focus and other settings.

At this stage, some cameras will then activate and deactivate the sensor when the shutter button is pressed to take a photo.

Other mobile cameras take things further and introduce a second and brighter super-quick light to further illuminate the scene right after the first light and just as the shutter goes off.

The current that runs through the diode for it to produce light comes from the battery. If the battery level is low, you will most likely not be able to use the flash at all.

Advantages and disadvantages of mobile LED flash

The upside of LEDs is that they can be quite small, thus making them perfect for modern smartphones where thin is king. And because they’re energy-efficient, you can rest assured that they’ll go easy on your battery.

Also, LEDs can run continuously, which can be useful when recording videos. This is also what makes the torch/flashlight feature on your smartphone possible.

However, the smartphone camera LED flash is known to be quite dim compared to other types of professional flash technology. Consequently, the area illuminated by the LED flash tends to be small.

This results in pictures that appear illuminated in the foreground but still very dark further away from the camera.

LEDs are slow lights which makes them not ideal for photographing fast-moving objects. Coupled with using slow shutter speeds, if you’re doing action photography with your smartphone camera using LED flash, you will be disappointed in the lack of crispness in your photographs. Xenon flash works best for capturing sharp images of fast-moving action.


Types of smartphone camera LED flash

LED flash comes in various types

Single-LED flash

This is a very simple flash setup that is made up of only one LED light that commonly gives off a white light.

The issue with this type of flash is that it’s quite dim compared to the other types of flash. As a result, it doesn’t illuminate a large area. The pictures end up looking washed out and lit in the foreground but dark in the background.

Dual-LED flash

To combat how dim single-LED flash can be, a lot of smartphone manufacturers introduced what is known as dual-LED flash. This type of flash works just like the single LED flash but instead of one LED it has two.

In a lot of cases, the two LEDs of the mobile camera’s flash give off light of two different colour temperatures. One produces a warm coloured light and the other a cool coloured light.

However, it is possible to have a dual-LED flash that fires off only one colour temperature light. This is usually a white light similar to that of the single-LED flash.

Difference between Single-LED and Dual-LED flash

The main difference between single-LED flash and dual-LED flash is the brightness of the light and how far it can reach. A dual-LED flash can produce twice as much light as a single-LED.

Because of the inverse square law of lighting, this means you can light subjects 1.4x further away with a dual-LED flash than a single-LED flash.

However, brightness is not the only difference between these two types of LED mobile camera flashes. Have a look at the table below:

Single-LED vs Dual-LED
Single-LED flash Dual-LED flash
Small in size Bigger in size to accommodate two units
Uses very little power Uses more battery power
Inexpensive More costly
Dim Provides more illumination
Adds bluish tint to photos Can feature dual-tone flash
Provides continuous lighting Provides continuous lighting
Moving objects may appear blurry Moving objects may appear blurry
Triple-LED and Quad-LED flash

Some smartphone makers have taken things even further and put together triple-LED and quad-LED flashes for their cameras. Except for the increased brightness of the flash they give off, these are no different to the dual-LED flash.

What is a dual-tone flash?

One of the problems with single-LED camera flash is that it can cause photos to look a bit bluish. This is because the light it gives off is a ‘cool’ white light. It does not generally match the ambient light temperature of the environment.

Dual-tone LED flash aims to remedy this problem by using LEDs of two different colour temperatures— one “warm” and the other “cool”. The idea behind this type of flash technology is to have a balance between the two colour temperature LEDs to create a better fit for the lighting of the environment.

dual-tone dual-LED flash unit

When taking a photo with a mobile camera that has dual-tone LED flash, the camera analyses the scene and computes the ambient lighting of the environment. The dual-tone LED flash will then set off the two different coloured LED’s at varying intensities to match the lighting of the area.

Based on the colour temperature of the ambient lighting, the phone cleverly tries to figure out the ideal ratio of power between the two flashes that will be a better natural match for the environment.

Some manufacturers may have different names for dual-tone LED flash. Apple, for example, calls it True Tone flash on their devices.

Xenon flash

nokia phone with xenon flash

Nokia phone with xenon flash

Perhaps you’ve seen or heard of a xenon flash before. It’s everywhere in professional flash photography but not so much on mobile phones. That’s because they come at a heavy price, and I’m not just talking about the cost. Not only is xenon expensive, but it also consumes a lot of power.

Though not so popular anymore, some smartphone cameras in the past, particularly Nokia phone cameras, had xenon flash. This is the same type of flash you’d find in traditional photography.

It’s a very powerful and impressive type of flash but it’s rather expensive, bulky, and power-consuming. It also doesn’t provide continuous lighting, so you can’t use it as a phone torch or as lighting for recording video.

How Xenon flash works on smartphones

illustration of how xenon flash works

Xenon flash is made up of a tube that looks similar to that of a neon or fluorescent light. This xenon gas-filled tube has electricity conductors on either end and a metal trigger plate running through the middle of the tube.

A circuit connects the power from the phone’s battery to the discharge tube. When an electrical current is conducted through the tube, the xenon atoms emit light and then-- BOOM! There’s your flash!

Just like with LED flash, Xenon flash is activated and deactivated in the camera app. If it’s enabled, a current will be sent through the xenon tube and it will give off a flash. A distinct difference between the two is that xenon flash does not provide continuous lighting.

This means you won’t get that first stage of prolonged light you get with some LED flashes that helps the camera adjust itself to take the best picture possible under those lighting conditions.

Advantages and disadvantages of xenon flash on mobile cameras

Light from a xenon flash travels further and illuminates far more than light from an LED flash does. And when it comes to moving objects, xenon flash is able to capture pictures without the motion blur associated with an LED flash. This makes xenon ideal for action photography where the subject is constantly moving.

LED flash vs xenon flash motion blur

Left: LED flash image has motion blur. Right: Xenon flash has no motion blur. Source: gadgethouse.com

The problem with xenon flash is that it’s expensive, bulky, and it drains power. Therefore, it’s not an ideal option for modern smartphones where size and battery life matter more than anything.

Also, xenon flash cannot provide continuous lighting like the LED flash can, which means it can’t function as a torch nor can it provide lighting for video. That’s a real downside if you want to capture video in low light.

Phones with xenon flash

Sure, xenon flash has some serious downsides for mobile cameras but that is not to say that there haven’t been any mobile phones that have used xenon flash with their cameras.

Nokia n8 with xenon flash

Nokia N8 with xenon flash

Some years ago, Nokia phones such as the N82 and N8 (released in 2007 and 2010 respectively) used xenon flash. The most recent phone to have xenon flash is the Samsung K Zoom, which was released in 2014. What was unique about it is that it had both a xenon and an LED flash.

Today, you won’t find any popular smartphone that has a camera with xenon flash. Whether or not future handsets will have xenon flash is debatable. Smartphone manufacturers seem to be leaning more and more towards computational photography to deal with the challenges of mobile photography in low light rather than adding costly hardware.

LED flash vs. Xenon flash

LED flash Xenon flash
Small in size Can be quite bulky
Uses little power Requires a lot of power
Inexpensive Expensive
Dim The light is brighter and travels further
Provides continuous lighting Cannot stay lit continuously
Moving objects may appear blurry Perfect for fast-moving action shots

Should you use the flash on your smartphone camera?

Whether you should or shouldn’t use the flash on your smartphone camera is entirely up to you. Photography is a purely subjective art form, so you can do whatever you want.

However, ideally, as often as possible, you should avoid using the flash on your phone camera.

The reason anyone would consider switching on their mobile camera’s flash is that they’re in a poorly lit environment and they need to illuminate the shot. Honestly, it’s better to go to an area that has a decent source of light than to use the flash on a phone.

This is because smartphone camera flash is limited in power and functionality compared to the flash used by professional photographers. It’s just another one of those factors that make a smartphone camera and a DSLR so different.

But in all fairness, not all smartphone camera flash is terrible. They don’t all have the same type of flash. Some perform better than others, though still within their limits.

Disadvantages of an on-camera smartphone flash

One of the problems with smartphone camera flash is that its position is fixed and therefore cannot be adjusted. And because light from the flash hits the subject straight on, it often causes red eyes.

Not only that, but you also can’t move the light around to mould your subject. The image ends up mostly looking flat and overlit. The subject closest to the camera will most likely look too bright with some harsh shadows while everything further away from the camera looks darker.

Another downside to using the flash on smartphone cameras is that you can’t control it. In most cases, when you take a picture with the flash activated on your phone, it fires off automatically without your intervention. You don’t get to choose the intensity of the light, its speed, colour temperature, etc.

How to turn off your smartphone camera flash

The flash for a mobile camera is controlled from the camera app. Whether you’re using auto or manual mode, you should be able to enable and disable flash the camera app’s home screen. You can identify the flash setting by the lightning icon.

There are usually three settings for flash:

  • Off: This means that flash is disabled and will not go off when the shutter is activated. The symbol for this is usually a circle with a lightning icon in the middle and a line running diagonally through it.
  • On: The means that the flash is activated and will go off every time the shutter button is pressed regardless of how much lighting is already in the scene. The symbol for this is the common lightning icon.
  • Auto-flash: This setting puts the camera in charge. It will analyze the lighting of the scene and calculate whether it is adequate or it should activate the flash to add extra lighting. The sign for this is a lightning icon with the letter ‘A’.

To activate the different settings, you may have to tap on the flash icon until the setting you want appears. If the flash setting is not on the home screen of your camera app, then it might be in the camera settings.

Alternatives to on-camera smartphone flash

Flash photography with a smartphone is not entirely impossible. There are a few reputable companies such as Profoto and Godox that have external wireless flash units specifically for smartphones.

external wireless smartphone camera flash in action

These flash units sort of work similar to external flashes for traditional cameras. You can move them around and place them wherever you want. The flash is triggered remotely from the phone when a picture is taken.

What’s great about these is that you can control the settings of the flash so you can get the exact lighting you want.

If you’re not interested in investing in a dedicated external flash unit for your smartphone camera, you can get your hands on a mobile continuous light unit. These LED lights don’t flash when taking a photo but rather remain lit once they’re switched on.

Because of this, they’re versatile enough to be used for mobile photography and for creating mobile video content such as vlogging.

Flash for selfie lovers

In the past, cell phone manufacturers weren’t too concerned about the picture quality of the front camera as much as they were with the rear camera. This obviously changed the more selfies gained popularity.

Now, not only do you get front cameras with more megapixels than some phones’ main cameras, but you also get different types of flash for these cameras.

Built-in front camera flash

Redmi note 5 pro with LED selfie flash

In recent years, smartphone manufacturers have started including front-facing LED flashes to their devices. These work just the same as the rear LED flashes described earlier.

However, in most cases, front camera flashes tend to be single-LED flashes. Most instances of dual-LED front-facing flash come from phones with motorized pop-up cameras or ones with rear cameras that can be flipped to face the front.

What I also found interesting is that a lot of the times, it’s mostly mid-range devices that have a front camera flash. Very few, if any, high-end flagship phones have front-facing flash. I did extensive research into this but I found no answer as to why this is the case.

Screen flash

Another option to light up photos taken with the front camera is known as ‘screen flash’. This is where the phone’s screen turns a bright white as the picture is taken to emulate the flash.

It isn’t the brightest of lighting but at close proximity, it does provide some illumination. Some devices and camera apps come with this feature readily available.

Effects of mobile camera flash on the eyes

The flash on smartphone cameras can be quite bright and damn near blinding, especially xenon flash. And after seeing many pictures of people with red eyes caused by the flash, one can’t help but wonder if perhaps that’s a sign that the flash could be damaging our eyes. And that’s a valid concern.

Is mobile camera flash harmful to the eyes?

The reality is that flash is not harmful to our eyes. If it was, it probably would have been outlawed by now because of how many generations of people it blinded.

Also, famous people like movie stars are exposed to hundreds of flashing cameras at a time and they all seem to be fine.

Even when it comes to small children and animals, there is no evidence that proves flash is harmful to them either. The light from the flash is too low in intensity and too unfocused for it to do any harm to the eyes or cause pain.

In fact, flash is no different than the light from the sun. It only seems bright because it greatly contrasts the dark environment in which it is set off. If the same flash was set off during the day, it would appear less bright than it does at night.

If anything, flash is just really annoying. And this is usually because of flash blindness, which is harmless and gradually fades after a second or so.

But, I’m no medical expert. There are those who perhaps have medical conditions that can be triggered by flash photography. It’s best to be safe than sorry. Speak to a medical expert if you have any concerns about using the flash on your mobile phone.

What causes red eyes when using flash?

If you have ever taken a photo with flash, you may have noticed that every now and then, the pupils of your subjects’ eyes appear red. As I mentioned before, flash is safe. The cause of red eyes is completely natural and nothing to worry about.

red eye effect caused by flash

What causes the red eyes is the light from the cameras flash that bounces off the blood cells in the eyes and is reflected back to the camera.

When we are in a bright environment, our pupils get smaller to restrict the amount of light that enters our eyes. This way, our eyes are not overwhelmed by too much light.

When we are in a dark room, our pupils grow bigger to let in as much light as possible, so we can see better. If someone were to switch on the lights after you’ve spent a while in the dark, you will probably squint your eyes to limit the harsh light until your pupils shrink and do that on their own.

So, if you have to take a picture using flash, that means that you are in a dimly lit environment. Therefore, your pupils are enlarged to allow as much light in as possible. When the flash goes off at the same time as the shutter, the pupil does not contract quick enough before the snap is captured.

illustration of how camera flash causes red eye

Because of this, a large amount of light enters the eye and illuminates the blood vessels inside. It’s the red colour of these blood cells in the eyes that is reflected back to the camera and appears on the photo taken.

How to avoid red eyes

The best way to fix red eyes is to avoid the problem altogether. Instead of using flash, find a more adequately lit spot to take photos. It makes for better-looking pictures. Otherwise, try as much as possible to avoid pointing the flash directly in your subject’s eyes.  

Some smartphones these days already have red-eye reduction capabilities built into them. As I mentioned earlier, some mobile camera LEDs light up continuously first before a second flash goes off to take the photo.

This helps reduce the probability of red eyes by giving the eye a chance to adjust the pupil to bright light before firing off the flash.

It’s not a foolproof system, so there’s still a chance that you could still come across the red-eye problem. What then? Photo editing apps and computer programs can fix that problem very quickly and easily in just a few clicks.

For a quick tutorial on how to remove red eyes from your mobile photographs, click here.

When to use flash

Flash can be a great lifesaver when you’re in an environment that has low lighting, especially if it’s one you have no control over so you can set up the proper lighting. You can also use the flash on a mobile camera as a sort of fill light, provided the subject is not very reflective.

You can also use the flash on your phone for creative purposes. Mobile photography is an art that’s about self-expression. If what you want to capture works best with the flash on your phone, then go ahead and use it.

I personally prefer not to use it often. In fact, I avoid using it as often as possible so I can capture good quality smartphone photos. No matter what type of flash smartphone cameras have, they tend to produce images that are less than satisfactory.

If you want to take well-exposed photos in low lighting, try these tried and tested methods to improve the brightness of your photos instead of relying on the flash. At best it should be a last resort.

free ebook download link

If you want to learn more about how to improve your smartphone photography by more than just improving the brightness of your photos, download the 5 Ways To Improve Your Smartphone Photography ebook by clicking on the banner above or by clicking here. There’s a lot to learn in its 22 pages of content and it’s ABSOLUTELY FREE!!!

As a bonus, here are some 15 Quick Tips on How To Take Amazing Photos With Your Phone. Enjoy!

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