Today as today we can take photos of good quality even when there is little light, for example in the evening, simply by bringing out the phone from the pocket. But how one succeeds smartphone To return such detailed images in conditions that, until a few years ago, would have put it completely into crisis? All this is thanks to the night modealso called “Night Sight”, a function that uses computational photography: a set of advanced software processing techniques that allow the phone camera to capture details that the human eye, or a single photographic exposure, would struggle to perceive.
In practice, when you activate the night mode, the phone does not take a single photo, but one sequence of images With different exhibitions. These are then automatically combined to obtain a single brighter shot, rich in details and with less noise (the annoying “grain” one that appears more easily in the photos taken in the dark). All happens in a few secondsthanks to increasingly sophisticated sensors and a software that recognizes, corrects and enhances each area of the image, without it is necessary to manually set values such as theISO or the shutter. The night mode can be set so that it is activated automatically Or manually and, depending on the manufacturer, it can integrate additional features such as those useful for astrophotography.
Let’s see more in detail How the night mode of the camera of our smartphones works And as it allows you to take much clearer, clear and balanced photos in not very enlightened environments.
How the night mode of the smartphone works
When you take a photo at night with yours smartphoneseveral consecutive shots come into play with different exposure times. The exposure is the amount of light that reaches the camera sensor: in low light conditions, to obtain a good image, it is necessary increase the time when the shutter remains openso that the catch sensor plus light. There quantity of light that enters the sensorstherefore, is much lower than the one that hit the film. The sensors, however, cannot be enlarged much, otherwise they would risk not entering a smartphone: for this reason, algorithms have been developed that deal with treating the entry light to amplify the signal and produce good quality photos.
In any case, a longer exposure time involves a greater risk of movement or micro-mano, which is why it is essential that the phone remains as stopped as possible during the shot. The ideal would be, in these cases, to place the smartphone on a stable surface or, even better, use a small travel tripod.
The night mode uses a variant of the technique called HDR (High Dynamic Range), which consists of combine multiple images of the same subjecttaken with different exhibitions, to obtain a final photo with a more extensive dynamic range. This means that the image will be able to represent both the darker parts (shadows) and the brightest ones (the high lights) in a balanced way. The goal is to bring out invisible details to the naked eye or too dark for a single exposure.
The concept of night method of the main smartphone manufacturers
Each manufacturer implements this principle differently, using owner algorithms: for this reason, a photo in night mode taken with a Apple iPhone It may appear different from a shot with a smartphone Androidfor example one of the series Samsung Galaxy or of the series Google Pixeldespite being technically similar in operation.
The top phones today also use a technique called Pixel Binningwhich consists in “merged” more pixels of the sensor to create a sort of “Super-pixel”larger and sensitive to light. This process reduces noise and improves the brightness of the final image. It is one of the reasons why you can get good night shots even without using the flashwhich often produces unnatural results or with too clear shadows, which make the photo flat and unnatural.
Applefor example, introduced the night mode with iPhone 11 And since then he has made it available on all cameras of the subsequent models, including ultra-grandangolar and telephoto lenses. The system is automatically activated when a low environmental brightness is detected, and also allows you to manually adjust the exposure time to have greater control. If the iPhone detects that there is movement in the scene or that you are moving the phone, it provides you with help to achieve the subject better and improve the alignment of multiple shots.
Also Google He made school with the function Night sightwhich made its Pixel smartphones of the absolute references in dark photography. Its variant of astrophotography, for example, allows you to capture details of the night sky – stars, constellations and even the Milky Way – with a surprising sharpness, normally unattainable for most pocket cameras.
Samsungfor its part, has focused a lot on what she calls Nightographya mode optimized with artificial intelligence that combines up to 30 images in one shot. This allows you to reconstruct colors, textures and brightness even in extremely unfavorable conditions, such as urban nights or concerts.
Keep in mind, however, that to obtain truly satisfactory results, it is always useful that there is at least one source of environmental lighteven minimal. A slim lamp, a newly or car headlights of a car can help the algorithm to better reconstruct the scene, giving shots that do not require varied retouching and pastrocchi in post-production.
