The physical size of the sensor is important in digital photography. Very important. The surface of the collector deeply conditions its ability to collect light, so if we compare two sensors with the same technology and different dimensions, the largest there will always be more light. When conditions are unfavorable and this resource is scarce, having a large sensor can help us take less noisy and more detailed photos in shadowy areas.

Also, if its resolution is adequate and not excessive, a large sensor’s photodiodes are also large, allowing each to collect a lot of light and avoid aggressive post-processing that often degrades our photos. If we stick to smartphones with the photographic profession, their peak for now are one-inch sensors that aren’t exactly new beyond the noise they make.

Sony, Leica or Sharp are some of the mobile phone manufacturers that have placed terminals equipped with one-inch sensors in stores in recent years. Last year, Xiaomi launched the 12S Ultra, a smartphone equipped with a 50.3 megapixel IMX989 sensor manufactured by Sony. 1.6 µm photoreceptorsand repeated the same move with its new flagship photo cell phone.

A few hours ago, this Chinese brand introduced the Xiaomi 13 Pro, which houses the same sensor in the main camera. In addition, it has the support of Leica, an experienced and highly respected German camera manufacturer, which, according to Xiaomi, is actively involved in the fine-tuning of the cameras of this terminal. We’ve already had the opportunity to analyze it in-depth, and while we love it, its arrival reminds us that getting the most out of a one-inch sensor in a mobile phone is not easy.

Smartphones don’t make it easy for one-inch sensors

Before we go any further and to give some context, it’s worth taking a look at what is probably the most ambitious photography smartphone ever: Sony’s Xperia PRO-I. This 1,800 Euro mobile phone has a 1-inch, 20-megapixel Exmor RS CMOS sensor on the main camera. 2.4 µm photoreceptors It works hand in hand with a dual aperture optic (f/2.0 and f/4.0) made by ZEISS.

These specs on paper look great. In fact, this terminal looks more like a compact camera disguised as a smartphone than a traditional mobile phone. Regardless, beyond the advantages of having a sensor with 2.4 µm photoreceptors, it has an Achilles heel: the sensor’s usable resolution is 12.2 megapixels, not 20 megapixels. Almost 8 “lost” megapixels are unusable, because the optics manage to occupy only the middle area of ​​​​the sensor.

It is not easy to develop high-quality optics for a mobile phone that is bright and manages to minimize chromatic aberration and geometric distortion. And above all, not because of the very limited space available inside. Sony engineers could have supplied the main camera of the Xperia PRO-I with optics that could collect light and reflect it over the entire surface of the one-inch sensor (which is what they did with the RX100 VII camera), but in this case this smartphone it would be thicker, heavier and perhaps larger. And most of the users will probably reject such a stack.

One thing we can be sure of: Xiaomi and Leica engineers faced the same problem during the development of the new Xiaomi 13 Pro. In fact, my colleague Ricardo, editor of Xataka and preparing the analysis of this smartphone, emphasizes one thing. What we can’t ignore in the results: Shooting in RAW mode allows us to use only the 12-megapixel sensor, not the 50.3-megapixel sensor it actually has. Its performance in risky shooting scenarios is very good, as Ricardo explains, but it is a pity that this mobile does not get more than the RAW sensor.

For us, this is the biggest debt of smartphones equipped with a one-inch sensor. It is currently unclear whether miniaturization of conventional linear optics will solve this problem in the short term, but it is possible periscopic targets because they allow a large number of optical elements to be stacked.

And meanwhile, they solve the limitations imposed by the small vertical space available inside a mobile phone. We’ll see what happens. Regardless, the good news is that photography enthusiasts have at their disposal such appetizing smartphones as Sony’s Xperia PRO-I or Xiaomi 13 Pro, and other terminals with a pronounced photography profession. The potential of photo gear is undoubted, but the most important thing is that it gives us a wealth of creative capabilities.