Why 4 cameras on Xiaomi smartphone: module analysis

The modern mobile photography market is booming, and the number of lenses on the back has become one of the top marketing metrics. Once a single camera was enough for basic shots, but today a multi-modular system has become the standard even in the budget segment. Consumers often wonder if they really need all these extra sensors or if it's just a marketing ploy to increase the cost of the device.

Xiaomi is actively implementing three- and four-module circuits in its Redmi and Mi lineups, trying to offer flagship functionality at an affordable price. In this article, we will detail the purpose of each lens, explain the physical meaning of their work, and help you understand which ones are really useful in everyday life, and which remain only auxiliary tools.

Understanding the principles of optics will allow you to make more informed choices when buying a new gadget, you will learn to distinguish between real optical stabilization and software improvements and understand why having four cameras does not always guarantee better photo quality than having two but better modules.

The main module: the foundation of mobile photography

The core module is the central element of any system, and it accounts for 80-90% of all images taken in everyday life. In Xiaomi smartphones, this sensor usually has the highest resolution and the most aperture optics, allowing you to get quality shots even in low light conditions.

The physical size of the matrix is critical here. The larger the physical size of the sensor, the more light it can capture per unit of time. Xiaomi's current flagships use 1-inch sensors, which brings the quality of mobile shooting closer to entry-level SLR cameras, and it is this module that is responsible for natural background blur and detail.

Importantly, the core module is often devoid of optical zoom, relying on digital zoom or telephoto lenses, but it is image processing algorithms such as HDR and night mode that are primarily geared toward the main sensor, and the quality of the glass and aperture is always more important than any other camera on the body.

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When shooting indoors, try to use the main module, even if there is a wide-angle one, which will provide better detail and less digital noise in artificial lighting.

Wide-angle camera: capture space

The second most important module is the ultra-wide camera, which is designed to capture the widest possible frame, which is indispensable for shooting architecture, landscapes or group photos in cramped spaces, and the viewing angle of such lenses in Xiaomi smartphones often reaches 120 degrees.

But here's an important nuance: In budget models, the resolution of a wide-angle sensor is often underestimated (for example, 8 or 13 MP vs. 48 or 64 MP main), which leads to loss of detail at the edges of the frame and the emergence of distortion, the "fish-eye" effect, when straight lines are curved. flagship models Xiaomi solve this problem by installing high-quality wide-angle modules with autofocus.

Using this module, you can create dynamic frames with an exaggerated perspective. Software distortion correction algorithms in the MIUI or HyperOS shell automatically straighten lines, but sometimes this leads to the edges of the frame being cropped. For video, the wide-angle is also useful because it provides stabilization by trimming the edges of the frame.

• 🏞️ Ideal for shooting landscapes and urban architecture in confined spaces.
• 👥 Allows you to fit a large group of people into the frame without having to go far.
• 🎥 Adds dynamics when shooting video, creating an immersion effect.

Macro lens: myth and reality of detail

The fourth camera in the array is often a macro lens, and marketing has positioned it as a tool for shooting small objects at close range, theoretically allowing focus to be 2-4 centimeters away from the subject, which is not available to the main module without losing focus.

In practice, on Xiaomi mid-range and budget smartphones, the macro camera is often a low-resolution (2MP or 5MP) fixed-focus sensor, with images from such a module usually inferior to the main one, even if you do crop (trimming) of the central frame, due to the small size of the matrix and simple optics.

⚠️ Note: Don’t expect a built-in macro module in Xiaomi’s budget to be as good as a dedicated macro lens. Often, the images are soft and incomplete, especially when there’s not enough light.

However, the presence of such a module gives the user the opportunity to experiment. For shooting textures, insects or small details in static conditions, it can be useful if you can not get closer to the main lens. In more expensive models Xiaomi macro successfully takes over the wide-angle camera with autofocus, providing significantly better quality.

Depth Sensor and Telephoto Lens: Zoom and Portraits

The fourth element in a 4-camera configuration is often either a depth sensor or a telephoto lens, and the two modules perform fundamentally different tasks, and their presence dramatically changes the smartphone’s capabilities.

The depth sensor is essentially a low-resolution auxiliary camera that doesn't take pictures on its own, and its job is to map the depth of space by determining the distance to objects, and it's necessary for the quality of portrait mode, where the background is programmatically blurred, and without that sensor or lidar, blur can work incorrectly, eating away at the edges of objects.

Telephoto lens is a full-fledged optical zoom. Unlike a digital approximation that just stretches pixels, a telephoto lens has an optical focal length (usually 2x, 3x or 5x). Xiaomi Mi series and Xiaomi numerical series smartphones often feature periscopic telephoto lenses that allow you to get 10x optical zoom without loss of quality.

Software processing and synergy of modules

Having four cameras is only half the equation. The other half is processing algorithms and artificial intelligence that combine data from all sensors, and in Xiaomi smartphones, the image processing processor (ISP) and neural network engines are responsible for this.

When shooting in night mode (Night Mode), the smartphone can simultaneously use data from the main and wide-angle modules to reduce noise and expand the dynamic range. When switching zoom, the system smoothly moves from one lens to another, using data from neighboring cameras to predict color and detail, so that the transition is invisible to the user.

But software interpolation has its limits. If you use 10x zoom on a device without a periscopic lens, the result will be digital. This is where machine learning comes in, which is coming up with details, but this is not real optics. Xiaomi is actively working to improve these algorithms, but the physical size of the optics remains the main limiting factor.

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The quality of the final photo depends not only on the number of cameras, but also on the ability of the smartphone processor to correctly switch between them and process data in real time.

Configuration comparison: 3 vs 4 cameras

Consumers are often confused by the difference between three and four-camera models. In Xiaomi’s lineup, it’s often a matter of positioning. Three-camera models typically lack either a macro module or a depth sensor, relying on the software’s depth detection methods (Dual Pixel AF).

Having a fourth camera in the form of a macro lens or depth sensor in the budget segment is often a compromise. It is cheaper for a manufacturer to add two simple 2 MP sensors than one high-quality telephoto lens. Therefore, in the segment up to 20-25 thousand rubles, 4 cameras are more marketing than a real advantage in quality.

And in the top models, it's different. So the 4th camera is a telephoto lens with a periscopic lens system, and it really expands the functionality of allowing you to capture the moon, birds, or architectural details from a long distance without losing quality, and each camera is a complete tool.

• 📉 In the budget segment, the 4th camera is often a stub for marketing.
• 📈 In flagships, the 4th module is a full-fledged telephoto lens with optical zoom.
• 🧠 Software processing is more important than the number of physical lenses in cheap models.

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