What is a periscope camera on smartphones?
since the HUAWEI P30 Pro went official, the smartphone industry has been abuzz with the term periscope camera. And now that Samsung has equipped the Galaxy S20 Ultra with one such system that provides a whopping 100X space zoom, everyone is again talking about periscope cameras and how they can change the zooming capability of smartphones. But what exactly are periscope cameras? Well, read on to find out:
What it looks like?
A periscope camera derives its name from the eponymous instrument used on ships or submarines that allows users to see objects above the sea level, or anything else that is not in the direct line of sight. It essentially uses a combination of mirrors or a prism to bend light. Smartphone makers have used the same concept to create periscope modules for cameras to enhance their zooming range. Here’s how a periscope camera system looks on smartphones
But why periscope cameras?
When it comes to cameras, the lens body protrudes from the main kit and also extends out when needed. Doing so also pushes forward the lens and the internal array, providing an optical zoom that is lossless and does not affect image quality while zooming. However, the sleek form factor of a phone does not allow so much space. This is because there needs to be more gap between the sensor and lens elements to move vertically and create the optical zoom range, which is not possible in the cramped space of a smartphone.
However, using a periscope architecture lets designers arrange the lens and sensor in such a way that lens element have more space to move, thereby extending the optical zoom range significantly. This is achieved by using an L-shaped tunnel. The top end has a rectangular opening for collecting light which then falls on a prism. The prism bends the light at 90-degree which then passes through the lens elements and then falls on the sensor where it is processed.
A longer tunnel increases the gap between lens elements and the sensor so that the scope of movement is higher for the lens, which directly means higher zoom output. When users adjust the zoom level in the viewfinder, the internal lens elements move away from the sensor to provide the necessary zooming effect.
What are the benefits?
The maximum optical zoom range provided by periscope architecture is higher compared to a phone with a regular 2X telephoto camera with the lens elements stacked vertically. In such cases, if you want to increase the optical zoom, the camera bump has to be much, much thicker, which is simply not feasible for a phone
However, smartphone makers have the flexibility to make the periscope tunnel longer by slightly altering the other internal components of the phone, further increasing the optical zoom capacity in the process. This also increases the hybrid zoom output, which is significantly better than the digitally zoomed images.
If a phone has a periscope telephoto lens, it can provide a hybrid zoom range of 10X or even higher depending on the tunnel length and lens element arrangement. But a phone that has a vertically stacked fixed range telephoto lens will be limited to a smaller optical and hybrid zoom range. And at the end of the day, periscope design is what makes the crazy 100X Space Zoom on the Galaxy S20 Ultra possible.
Which phones have it?
The first phone to come equipped with a periscope telephoto lens system was the Huawei P30 Pro, and as expected, it impressed everyone with its raw image output and zooming capabilities. Samsung’s Galaxy S20 Ultra again brought the periscope cameras into the limelight.
But using periscope camera hardware in a smartphone is quite an expensive process, which is why they are limited to flagship phones only as now.
