Your smartphone has a 20MP sensor with f/1.8 OIS lens – And you have no idea what that means

Every time there is a new smartphone launch, we get bombarded with tons of numbers and specifications.

One of the main culprits is a device’s camera team, who love displaying long lists of their component’s latest features.

Here’s an example of a modern smartphone’s camera specifications:

  • 12MP main camera with wide-angle f/1.8 OIS lens, 12MP telephoto camera with f/2.4 OIS lens.
  • Phase-detection autofocus with touch focus.
  • Quad LED true-tone flash with slow sync mode.
  • Portrait mode with portrait lighting.
  • 4K video @ 60fps.
  • 7MP “selfie” cam with f/2.2 lens, face detection, and portrait mode.

For most people, you read the megapixel number and go “Yes, that’s higher than last year, this camera is better”.

“Ah, 4K video at 60fps, I need that” is another line you are likely to hear.

Unfortunately, most smartphone buyers have no clue what they are getting when they read a camera’s specifications – which is understandable, considering how many elements there are.

Understanding your camera

The first step to understanding your camera is to understand the terms used by smartphone makers.

A good resource is DxOMark, which ranks the performance of smartphone cameras using a numerical score.

The site’s glossary also lists many terms used to describe the abilities of cameras, including those used by smartphone makers.

Below are several of the key terms you are likely to encounter.


“Ratio of effective focal length and entrance pupil diameter of a lens; same as F-number. The smaller the aperture, the faster (brighter) the lens.”

The aperture is shown as f/1.8 in the example above. The smaller the f-stop number, the wider the opening of the lens.

This lets in more light and produces better low-light pictures, and produces less noise. Additionally, the lower the aperture number, the shutter speed time required for a set amount of light capture is reduced. This reduces blurring.


“Resolution describes the ability of a camera to resolve fine details. Both the lens and the sensor have an impact on resolution.”

Resolution on smartphone cameras is defined in megapixels – MP – and refers to what it can capture. (1MP is one million pixels.)

While a higher resolution means more pixels – which is usually indicative of higher quality – it is not as straightforward with cameras.

Former Apple software engineer Nikhil Bhogal told Time that pixel quality matters more than the number of pixels.

If a camera has good pixel quality, which can mean making individual pixels larger, it can improve photo quality.

In short, a higher MP count does not always mean a better camera. Super-high MP stats are also not always necessary – For example, a still from a 4K video is 8MP.

iPhone X Camera

Dual cameras

A dual-camera system means there are two cameras which make up one unit, which is typically on the rear of a smartphone (the primary camera).

A dual system can take the form of two cameras which have different focal lengths, for telephoto shots, or it comprises two sensors which create a combined image.

This sees the smartphone capturing more detail in an image via a colour sensor and a monochrome sensor, compared to a single-sensor camera.

4K @ 60fps

4K @60fps is a popular benchmark for cameras, and smartphone units often tout this video-capturing ability.

4K, often called UHD or 2160p, refers to the resolution of the video and is generally accepted as 3,840 x 2,160.

The 60fps refers to 60 frames per second, and means the camera can capture – you guessed it – 60 video frames per second.

The more frames per second the camera can capture when shooting video, the smoother the recorded content will look – particularly with action scenes and movement.

Most movies we watch are displayed in 24fps, and a 60fps video may seem “fast” if observed for the first time.


“Optical Image Stabiliser is a mechanism used to stabilise the recorded image by varying the optical path to the sensor. Typically, optical stabilisation is implemented through a moving image sensor or lens element.”

Simply put, smartphones with OIS have a mechanism which reduces blur in your photos by moving the sensor or lenses to counteract movement of your hand or body. This results in crisper images.


These are only the basic terms, and if you are buying a new smartphone and really want to know what its camera can do, take a fews minutes to read its specs and search for what you do not understand.

This will go a long way in helping you make the best decision.

Now read: Smartphone charging myths – Are you killing your battery?

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Your smartphone has a 20MP sensor with f/1.8 OIS lens – And you have no idea what that means