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Smartphone cameras have come a long way from the days when they had only one lens. Back then, you had to make do with whatever your single lens could capture, whether it was a wide shot or a close-up. But roughly since 2016, multi-camera phones have become the norm, and zoom lenses have opened up new possibilities for photography. Now, you can get closer to your subjects without losing image quality.
However, not all zoom lenses are created equal. The early ones were telephoto lenses that could only go up to 3x zoom. That’s nothing compared to the 100x zoom that some of the latest smartphones flaunt. How did they achieve this feat? The answer is periscope lenses. In this article, we will explore what periscope lenses are, why they are superior, and how you can get your hands on one.
A periscope camera is a type of camera that lets you zoom in on faraway objects without losing image quality or making your smartphone thicker. It uses a smart optical trick that bends the light at a right angle, similar to how a periscope works in submarines or tanks.
For example, suppose you want to take a photo of a bird on a tree branch, but it is too far for your regular camera to capture it clearly. You could use a telephoto lens, which is a long tube with many lenses inside that make the image bigger. But to get enough zoom (say, 10x), the tube would have to be very long and wide, which would make the phone too thick.
A periscope camera avoids this problem by reflecting the light 90 degrees through the lenses and onto the sensor. This way, it can fit more lenses and be more powerful without making the phone thicker. But how does the light from the bird reach the sideways camera? This is where the prism comes in.
A prism is a device that uses mirrors or glass to change the direction of light at right angles, allowing you to see around obstacles. A periscope camera uses a prism at the end of the tube, opposite to the sensor, to turn the light by 90 degrees. The light enters through a small opening on the back of the phone, hits the prism, and then travels along the tube to reach the sensor.
This way, you can zoom in on the bird with 5x or 10x optical zoom, which means that the image is enlarged by the lenses and not by software. Optical zoom keeps the original quality and details of the image, unlike digital zoom, which just cuts and stretches the image.
The best way to tell if the zoom lens on a smartphone is the periscope or telephoto variety is by looking at its shape. A telephoto camera has a circular opening, which is the standard shape for most cameras. Meanwhile, a periscope camera has a rectangular opening, which is unique and easy to identify.
Another difference, as discussed above, is the orientation of the lenses inside the camera. A telephoto camera has a straight lens arrangement, which means the light enters the camera and passes through a series of lenses in a straight line before reaching the sensor. A periscope camera, on the other hand, has a right-angle lens arrangement, which means the light enters the camera and is reflected by a prism or a mirror at a 90-degree angle before passing through the lenses and reaching the sensor. This allows the periscope camera to have a longer optical path without increasing the thickness of the camera.
Since periscopic implementations allow greater space inside the camera system, they pack more lenses and help you get closer to your subjects. Compared to telephoto lenses which typically offer 2x or 3x zoom, periscope lenses zoom anywhere between 5x and 10x optically without increasing the thickness of the phone.
The more you zoom in, the greater the effects of movements on the image. That’s why periscope lenses need some kind of stabilisation mechanism to prevent blurry or shaky photos. One common solution is to use optical image stabilisation (OIS), which means that some part of the camera system can move in response to the phone’s motion and compensate for it.
In periscope lenses, OIS is usually applied to the prism, which can tilt or rotate along different axes to adjust the angle of the incoming light. This way, the prism acts like a stabiliser that keeps the image steady even at 10x zoom or higher.
Periscope lenses are a rare feature in smartphones, only available in the most expensive flagship models. For example, among the Samsung Galaxy S23 series, only the Ultra model (which costs over Rs 1 lakh) has a periscope lens that can zoom up to 10x optically. The other models have telephoto lenses that can only zoom up to 3x optically.
In India, the choices for periscope camera phones are very limited, as most Chinese brands do not launch their ultra-flagship models here and the iPhones do not have periscope lenses yet (although this may change with the iPhone 15 Pro series). The best and only proper zoom phone in the market currently is the Galaxy S23 Ultra offering 10x zoom, but the Pixel 7 Pro makes for an excellent, more affordable offering with its 5x lens.
If both these options are too pricey, then phones with telephoto lenses are good enough – there are many models that offer them. They may not have 5x or 10x zoom, but even 3x zoom makes a big difference.
