If you often take photos with your phone and have seen something like "periscope zoom" in the specifications, you've probably wondered what on earth that is and why it only appears on some high-end models. This type of camera has represented a huge leap forward in mobile photography: thanks to an ingenious optical trick, it allows to get very close to the scene without carrying around a bulky camera.Maintaining a quality that was unthinkable in a smartphone a few years ago.
In a short time we have gone from classic 2x telephoto lenses to mobile phones capable of offering 5x and 10x optical zoom and hybrid magnifications up to 100x or 120xAll of this is packed into slim, pocket-sized devices. Behind this "magic" are sideways-placed sensors, prisms, mirrors, L-shaped tunnels, advanced stabilization, and a hefty dose of AI processing to squeeze every last drop of performance from the ridiculously small space inside the phone.
What exactly is periscope zoom on a smartphone?
When we talk about periscope zoom on mobile phones, we are referring to a A telephoto camera that positions the lens and sensor perpendicular to the outer lens.Just like a small submarine periscope. The key is that the light doesn't enter in a straight line backward, but is deflected by a prism or mirror.
In a traditional camera (and in many "normal" mobile phone telephoto lenses), the lenses are positioned aligned just behind the opening you see on the outsideThis means that the longer the focal length, the more physical "depth" you need. If you tried to mount a long telephoto lens this way on a current smartphone, the module would stick out enormously and the phone would be much thicker.
The periscopic design turns the problem on its head: the sensor and lens assembly move. towards one side of the phone, horizontallyso that they are positioned at a 90-degree angle to the external lens. Between that small window you see on the back and the internal module, a prism or mirror system is placed that deflects the light at a right angle, much like a real periscope works.
Thanks to this trick, manufacturers can use much longer focal lengths (100 mm or more equivalent in traditional photography) without making the phone bulky. Compared to the 50mm focal length of many compact telephoto lenses, the periscope allows you to get much closer to the subject using real optical zoom and not just a simple digital crop.
This is how the periscopic mechanism works on the inside.
To visualize how it works, imagine the inside of the mobile phone as an L-shaped optical tunnelOn the side facing outwards, there is a small window—sometimes rectangular—through which light enters. This light first strikes a prism or a set of mirrors that deflects it 90 degrees to send it along the horizontal arm of the periscope.
Along that internal section, several lenses are placed responsible for to focus, direct, and magnify the image before it reaches the sensorSince the effective path of light is greater than the physical thickness of the device, a "long" focal length can be achieved without the camera protruding half a centimeter from the body.
In many designs, the entire system is assembled as an L-shaped sealed optical blockThe longer that internal arm is, the greater the reach that can be achieved: that's why in mobile phones with 5x, 7x or 10x periscope zoom the module occupies a good part of the internal board, even though from the outside you only see a small window.
This architecture allows the lens and sensor to have more space to “breathe” inside a very thin mobile phoneThis is impossible with a camera positioned in a straight line. The practical result is a truly powerful optical zoom without turning the phone into a brick or relying exclusively on algorithms to "invent" detail.
Why did the periscope zoom mark a turning point?
The big boom in periscope zoom came in 2019 with the Huawei P30 Pro, the model that popularized this technology among the general publicThis phone offered a 5x optical zoom when most phones were limited to 2x with much simpler telephoto lenses.
That 5x meant, in practice, that you could Get five times closer than with the main camera without sacrificing detailFurthermore, by combining that optical range with digital cropping and artificial intelligence, the P30 Pro offered a very decent 10x hybrid zoom for the time, making it a clear benchmark in mobile photography.
From then on, practically everyone jumped on the bandwagon. Samsung made a big bet with the Galaxy S20 Ultra and later with the Galaxy S21 Ultra and S23 Ultraincorporating periscope modules with high magnification and hybrid modes reaching 100x. Within the Android ecosystem, models like the Xiaomi Mi 10 Pro also shone, the My 10 Ultra with up to 120x hybrid zoom, plus the realme X3 SuperZoom and the OPPO Reno 10x Zoom and Find X2 Pro.
Advantages of periscope zoom lenses compared to other telephoto lenses
The great advantage of the periscopic zoom is that it allows achieve very high optical magnifications without increasing the thickness or size of the camera moduleBy relocating the sensor and lenses horizontally and using a prism to bend the light path, the internal space of the smartphone is used much more efficiently.
This translates into telephoto lenses with much longer equivalent focal lengths and a real zoom into the subjectwithout relying on aggressive cropping. Unlike digital zoom, here the magnification occurs physically in the optical system, maintaining greater sharpness, dynamic range, and fine texture.
Furthermore, the periscope offers incredible versatility. In a single phone, we can have an ultra-wide-angle lens (0,5x), a main sensor (1x), a short telephoto lens (2x or 3x), and a periscope long telephoto lens (5x or more)This range allows you to cover everything from very wide shots to distant close-ups without moving from your spot, as is the case with devices like the iPhone 15 Pro Max or the Galaxy Ultra.
Another advantage is that a good starting optical magnification of 5x or 10x allows the Rear hybrid zoom (20x, 30x, 50x, 100x…) It suffers less degradation. The additional cropping that needs to be applied is relatively small compared to doing everything from the main camera, and the AI algorithms can work with much more real-world data.
Optical, digital and hybrid zoom: how they differ
In mobile marketing, optical and digital enhancements are shamelessly mixed, so it's important to clarify the concepts. Optical zoom is the "old-fashioned" kind, based on physical opticsThis is achieved by changing the lens or moving elements of the lens so that the image reaches the sensor enlarged, without cropping the photo.
At the opposite extreme we have the digital zoom, which is simply an enlarged crop of the imageThe phone selects a central portion of the sensor, stretches it, and uses algorithms to create intermediate pixels. As you zoom in further, the result shows less detail, more noise, and a distinctly artificial appearance.
El Hybrid zoom combines the best features available at any given time.First, you zoom as far as possible with the optical zoom (for example, 5x with a periscope lens), and then you add digital cropping and advanced AI processing to zoom in further without a sudden drop in quality. It's an intermediate solution that, when implemented well, delivers amazing results.
In the current high-end range, processing has improved so much that a moderate digital zoom (up to 2x or 3x on the main camera, slightly more on a telephoto lens) It's quite usable for social media or on-screen viewing. But when it comes to large prints, very aggressive cropping, or low-light scenes, optical zoom remains the undisputed king.
How different types of zoom behave in real life
In everyday use, the periscope zoom shines especially in situations where you need great distance from the subject: wildlife, sports, concerts, distant monuments or basic astrophotographyWith a quality 5x optical zoom, you can capture close-ups that you couldn't achieve with the main camera without ruining the image through cropping. To delve deeper into night photography techniques and astrophotography, consult specific guides on night photography with mobile phone.
Some premium mobile phones already offer Up to 10x true optical zoom thanks to highly advanced periscopic modulesFrom there, hybrid modes come into play, which can offer quite good results up to 20x or so, and which reach the famous 50x, 100x or 120x, assuming that, from a certain point (around 30x), the quality drops more noticeably.
In portraiture, many brands use equivalent focal lengths between 85mm and 135mm to achieve a pleasing compression of features and a soft background blurA periscope telephoto lens with around 5x zoom can be perfect for closer, more dramatic portraits, provided there is sufficient light and the stabilization does its job well.
Right here appears one of the periscope's weaknesses: when working with long focal lengths and relatively small aperturesThe amount of light reaching the sensor is limited. This forces you to increase the ISO, which increases noise and necessitates aggressive processing to clean it up. Depending on the model, this can result in somewhat washed-out or less natural-looking images. If you experience problems related to ISO or focus, consult solutions for blurred photos in certain areas.
The big challenge: Zoom continuity on mobile devices
One of the greatest illusions in mobile photography is the sense of continuity when zooming from 1x to 5x or more. When you slide your finger along the zoom bar, It's not a single lens moving like in a professional video cameraIn reality, the phone switches from one fixed sensor to another (main, short telephoto, periscope) and fills in the intermediate points with digital cropping and AI.
This camera change causes, in many devices, abrupt changes in color, contrast, and level of detailThis is why, sometimes, a 3x photo looks worse than a 1x or 5x photo, despite being "closer" to the subject: in that intermediate range, the phone is performing digital acrobatics to disguise the sensor change.
To address this problem, some manufacturers are researching and presenting continuous optical zoom systems for mobile phonesThe idea is that, instead of two or three fixed focal lengths, the lens can smoothly vary within a range, maintaining sharpness and without color shifts. Something similar to a professional camera zoom lens, but miniaturized.
Sony tested something similar with some high-end Xperia phones with relatively short ranges, and LG also showed prototypes. More recently, Tecno presented a system called "Freeform Continuum Telephoto" which, on paper, It offers continuous optical zoom from 1x to 9x using physical principles based on the so-called "Alvarez lenses".
These lenses employ two freeform surfaces that They slide perpendicular to the optical axisBy moving one over the other, the overall power of the system varies, allowing the focal length to be changed without needing to lengthen the module like a telescope. If this approach takes hold, it could unify the range currently covered by the main camera, the short telescope, and the periscope into a single unit.
New designs: more compact periscopes and folding modules
In addition to continuous zoom, Tecno has showcased another concept called "Dual-Mirror Reflect Telephoto" that promises reduce the module's volume by half and the external height by about 10%.The key is to use coaxial optics based on several internal mirrors that bounce the light multiple times.
Instead of a single prism that deflects light 90 degrees, this system makes the beam of light travels through several “bounces” inside the module itselfby folding the optical path even further. This allows for long focal lengths in an even shorter physical path, a very attractive feature for continuing to manufacture thin mobile phones without sacrificing long telephoto lenses.
This design, however, has some curious effects: the presence of a Central obstruction produces donut-shaped bokeh instead of the classic circular blur. The manufacturer sells it as a distinctive artistic touch, but it's a direct consequence of the mirrors' optical geometry.
All of this is still in the development and prototype phase. The challenge is not only making it work, but making the system... sufficiently bright throughout the zoom rangeIf the aperture is too small, the ISO skyrockets, noise appears, and the processing has to work overtime, which brings us back to the same problem: too much dependence on software to "fix" the image.
Optical zoom vs digital zoom: which one interests you more
If we get technical, there's no comparison: Optical zoom always offers better quality than digital zoomIt maintains the sensor's native resolution, preserves dynamic range, generates fewer unusual artifacts, and generally performs better in low light. Furthermore, optical image stabilization (OIS) is typically very well-tuned in these dedicated lenses.
Digital zoom, on the other hand, has the advantage that It doesn't take up extra space or make the phone excessively expensive.That's why we find it even in very basic phones. With modern algorithms and artificial intelligence, up to 2x or 3x zoom from the main camera can get you by with decent results for social media or casual use.
The hybrid zoom based on a good periscope plays a very interesting role: starting from a high-quality 5x or 10x optical zoomThe additional cropping required to achieve 20x or 30x magnification is far less destructive than if everything were done using the main sensor. This is where high-end phones clearly differentiate themselves from more affordable models.
Which mobile phones have periscope zoom and typical zoom ranges?
In today's market, most of Mobile phones with periscope zoom belong to the high and premium segmentThis technology is available on both Android and iOS. Apple reserves it for its most advanced model, the iPhone 15 Pro Max, which features a very capable 5x optical zoom and a fairly usable 25x digital zoom.
In Android, Samsung has been pampering its periscopes for several generations in the Ultra family of the Galaxy S: the The Galaxy S20 Ultra debuted the design, followed by the S21 Ultra, S22 Ultra, and S23 Ultra., with long-range telephoto lenses and highly publicized 100x hybrid modes.
Despite trade restrictions, Huawei continues to offer P and Mate series with powerful periscopic systemsXiaomi has experimented with extreme ranges, such as the 120x hybrid zoom of the Mi 10 Ultra, relying heavily on computational processing to extract detail where the sensor is already struggling.
Brands like realme and OPPO have also joined the periscope telephoto trend: the realme X3 SuperZoom, the OPPO Reno 10x Zoom or the Find X2 Pro These are clear references to devices that used this architecture as a selling point, offering large increases in relatively small sizes.
In more affordable price ranges it is common to see small 2x or 3x optical zoom lenses without periscopic designSince L-shaped prism architecture remains expensive and complex, 2x zoom is relatively common in phones costing €300-€500, while long periscope lenses are usually reserved for devices priced above €700-€800.
Practical applications of periscope zoom in photography and video
In everyday photography, the periscope zoom is a delight for to capture distant details without having to physically get closerIf you enjoy photographing birds, wildlife, concerts from the stands, or players in a stadium, this type of telephoto lens is a game-changer.
For portraits, a 2x or 3x telephoto lens already works very well, but the jump to a 5x allows for... much tighter shots, with highly compressed backgrounds and a very pronounced blurCombined with portrait modes and aperture simulations, you can achieve a look quite similar to that of a camera with a dedicated telephoto lens, while respecting the limitations of the small sensor.
In video, periscopes are becoming key. The combination of optical and electronic stabilization allows record highly amplified clips without hand tremors ruining the shotHowever, achieving a smooth transition without quality drops throughout the entire zoom range is still more complicated today than in still photography.
In the professional environment of film or television, zoom lenses are designed with the continuity of framing, exposure consistency, and parfocal focus (so that the subject doesn't go out of focus when zooming). Carrying something similar to a tiny mobile phone module is precisely the goal of technologies like continuous zoom and the new folding periscopes with special lenses.
Other types of zoom that coexist with the periscopic zoom
Modern mobile photography features several types of zoom that complement each other. In addition to optical, digital, and hybrid zooms, many phones offer ultrawide zoom, high-resolution intelligent zoom, and various sensor cropping combinations to cover very different situations.
The so-called "ultrawide" zoom does not bring the scene closer; in fact, it does just the opposite: It greatly widens the viewing angle to encompass more elements in the frame.It's ideal for landscapes, architecture, or group photos where you can't physically move far enough away.
On the other hand, some manufacturers talk about high-resolution or intelligent digital zoomIt combines high-megapixel sensors with supersampling techniques and advanced processing. The goal is to simulate an optical telephoto lens, offering cleaner close-ups than a simple crop, and making better use of the sensor's enormous resolution.
Thanks to the combination of all these options—ultra-wide-angle, bright main camera, short telephoto, periscope, and advanced digital zoom—today's smartphones offer a huge creative range for taking photos from a distance without sacrificing too much qualityAnd, as optics improve and software stops "faking" the image so much, the result gets closer and closer to what you expect from a traditional camera.
Periscope zoom has become a kind of optical engineering trick that allows serious telephoto lenses to be fitted into thin and elegant phones. Thanks to prisms, mirrors, L-shaped tunnels, and new folding designs, it's possible to achieve spectacular close-ups supported by real optical zoom and increasingly refined hybrid modes.
There are still significant challenges — such as achieving continuous zoom, maintaining high luminance across the entire range, and reducing reliance on aggressive processing — but today it is the most complete solution for truly getting closer to the action with your mobile phone without sacrificing good image quality. Share this information so that more users can learn about the topic.