Gone are the days of single-camera smartphones. Today, if you buy a decent phone that can take good photos, chances are it will have more than one camera at the back. Some have two cameras while other smartphones have four or even five cameras at the back.
All in all, there are seven different types of cameras you can find on a smartphone. However, chances are you won’t find every single one of them on one phone. But what exactly are these cameras and how are they different from each other? What are they for?
In this article, we’re going to look at these seven different types of smartphone cameras and the sort of photos they can give you. But before you read on, I recommend you read through this article about focal length for everything in this article to make sense.
Typical smartphone focal lengths
This is by far the most common type of camera found on most smartphones. Back in the days of single rear cameras, the camera had a wide-angle lens.
Today, the primary camera that has the best specs on most phones is the wide-angle camera. Even the front-facing selfie camera most often has a wide-angle lens.
The focal length of the wide-angle camera on smartphones ranges between 22mm and 30mm. This short focal length gives the camera a wide angle-of-view, thus the name.
The wide-angle camera is ideal for capturing landscapes, group shots, or any other instance where you want to capture as much of the scene as possible.
As the name suggests, the ultra-wide-angle camera has an even wider angle-of-view than the standard wide-angle lens. However, this type of camera is not as common as the wide-angle camera, particularly as a lone camera.
Some smartphones have a dual front-facing camera setup with an ultra-wide-angle camera as a secondary front-facing camera next to the front wide-angle. That allows you to take selfies that can include more people or scenery in the frame.
The focal of an ultra-wide-angle phone camera is generally anywhere from about 12mm to 18mm. This gives you an angle-of-view of up to about 120-degrees.
The downside of ultra-wide-angle lenses is that the wider their angle of view is, the more distorted the images will look around the edges. It creates a bulging effect known as a fisheye. Good mobile cameras are able to fix the distortion and give you decent results.
The telephoto camera on a smartphone has a much longer focal length than the wide-angle camera. In most cases, it is two or three times the focal length of the wide-angle camera. This is what gives a mobile camera the 2x or 3x “optical zoom” factor.
The telephoto camera on a phone can have a focal length of anywhere between 50mm to 85mm. So, if the primary camera has a 26mm lens and the telephoto camera has a 52mm lens, the optical zoom factor is 2x.
Because telephoto lenses have a longer focal length than wide-angle lenses, they have a narrower angle-of-view. This makes the telephoto camera ideal for capturing portraits with your phone.
Telephoto lenses on smartphone cameras are limited to a low zoom factor due to size. Anything more than 3x optical zoom would result in a big bulge at the back, and nobody wants to repeat that mistake. Phones with bulging zoom lenses such as the Galaxy S4 Zoom did not sell too well, apparently.
To be able to zoom further without creating a bulge, smartphone manufacturers turned to an old technology that uses folded optics similar to those of a submarine periscope to capture an image. A prism reflects light that enters the camera and directs it to the sensor, which is positioned on its side.
Because it can zoom further than a standard telephoto camera, a periscope camera on a phone usually has a focal length of, more or less, 105mm to 130mm. Phones with a periscope camera often boast optical zoom factors of up to 10x.
For smartphone cameras to produce colour photos, an RGB (red, green, blue) colour filter array (CFA) is placed on top of the sensor. Without this filter, the camera would capture black and white images because a sensor on its own only detects light intensity, not colour.
The downside of the colour filter array is that it absorbs light waves that match the colour of the filter and reflects the rest. For example, a red filter absorbs red light only and reflects the rest, as do the blue and green filters with their matching light waves. This means quite a lot of light is reflected and wasted by the CFA.
Some smartphones use monochrome sensors without a CFA in order to capture as much light as possible, especially in low-light conditions. This usually results in images that are sharp and have high contrast. Most smartphones with monochrome sensors use what is known as computational photography to combine images from other sensors with a CFA to improve their overall appearance.
Depending on the phone, you can capture true black and white photos with the monochrome sensor as opposed to adding a digital black and white filter. However, some phones don’t allow you to take photos with the monochrome camera and only use the data from the sensor for computational purposes.
A macro lens is useful for close-up photography where you want to capture small details of the subject. A smartphone macro camera differs from the telephoto and periscope cameras in that it doesn’t zoom in on a distant subject, but rather it magnifies subjects that are close to the camera, much like a magnifying glass.
Although there are many mobile macro photography enthusiasts out there, not many phones have macro cameras, particularly high-end flagship smartphones. Macro cameras on smartphones are usually found on mid-range devices and phones popular in Asian markets.
The specs of most smartphone macro cameras aren’t as impressive as the other cameras on the phone. In fact, you currently can’t find many, if any, phones with a macro camera above 5MP. This has led many to believe that the macro camera on phones is useless. But that’s not entirely true. A camera doesn’t need tons of megapixels to take good photos.
ALSO READ: Smartphones With A Macro Camera
The final type of camera found on smartphones goes by many different names. A ToF (time-of-flight) camera, also known as a depth sensor, is not a camera used for shooting photos. Rather, it’s used to collect data for use in computational photography. Hence, it’s a generally low resolution (2MP or below) camera.
The purpose of the ToF camera is to create a three-dimensional map, or depth map, of a scene. This is done by shooting out a laser and calculating the time it takes for it to bounce off a surface and reflect back to the camera. This information is used to analyse what’s close to the camera and what’s in the background.
When taking portrait shots, that background/foreground information gathered by the depth sensor can be used to create artificial effects such as the blurred background that separates the subject from the background. This camera also provides information for AR (augmented reality) applications.
Smartphones don’t have multiple cameras just for the hell of it. Each one is different and serves a specific purpose. Phone manufacturers decide which ones to include in their devices, keeping in mind the budget and the space available on the phone.
Although having one camera on a phone was deemed more than enough in the early days of smartphones, having multiple cameras on a phone opens up more opportunities for creative exploration with mobile photography.