Liquid lenses seem to be the latest breakthrough in the evolution of smartphone cameras. The first effective liquid lens on a smartphone has already made its debut on the Xiaomi Mi Mix Fold. What are liquid lenses? Are they actually made of liquid? Why do we need liquid lenses?

A lens (in a camera) can be defined as a piece of plastic or glass, that is used to focus light onto an image sensor. Lenses are a very important part of a camera. They determine a camera’s focusing ability, the field of view it can capture, the distance at which it can capture objects, clarity of the image captured etc.

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The problem with lens optics on smartphones

For a lens to be effective, the focal length has to be adjusted manually to get the best focus on the object to be captured.

On professional grade cameras, lenses can be swapped. The focal length of these lenses can also be manually adjusted with the aid of a slider or roller.

On smartphones however, what we have are fixed lenses that are not adjustable. This means that the phone has a fixed focal length. So the user has to physically move the phone, either away from or nearer to the object being captured.

Capturing distant objects is also difficult for smartphones. This is because the lens cannot physically move to either zoom or compensate focus for the distance.

Manufacturers have found smart ways to mitigate this shortcoming e.g. Phase Detection Auto-Focus (PDAF), multiple lens set-ups and external lenses.

Some have also attempted to put proper adjustable lenses on a phone e.g. the Samsung Galaxy S4 zoom.

These so far haven’t brought lasting solutions. PDAF can be hit or miss, external lenses do not necessarily work as expected and adding a zoom camera to the back of a smartphone makes it bulky and difficult to manage.

So then, how can we get a smartphone lens to be able to physically move so as to adjust focal length? The solution: liquid lenses

What are liquid lenses?

A liquid lens can defined as lens system that is made up of one or more liquids. It was invented in 1995 by French Physicist Bruno Berge in the city of Lyon.

How do liquid lenses work?

Unlike traditional lenses that need to be manually adjusted, liquid lenses can be adjusted electronically to find the right focal length for an image.

Liquid lenses on smartphones are made up of two immiscible liquids. When current is passed through these liquids, they change their shape and curvature, thereby adjusting their focal length. The amount of current applied determines how much the shape of the liquid will change. This means that liquid lenses are capable of many focal lengths.

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Advantages of liquid lenses

The most important, especially for photographers is having a lens with multiple focal lengths that can adjust itself very quickly and automatically.

There are no mechanical parts to damage and they have a longer lifespan due to little wear and tear. They also have improved image stabilization and better close focusing abilities. They are a very good fit for smartphones because they can be very small and energy efficient.

The future

It remains to be seen if the use of liquid lenses will catch on due to several factors such as production costs and availability. But one cannot deny that due to the several advantages that liquid lenses have over their more traditional contemporaries, manufacturers will not turn a blind eye. So yes, in a few years from now, you may have one in your pocket.

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