The camera sensor is made up of millions of microscopic light-sensitive elements, called pixels. Each pixel reacts to incident light, generating an electrical charge proportional to the amount of light received. The more light falls on a pixel, the stronger the signal generated.
Types of Camera Sensors
CCD Matrix
CCD (Charge-Coupled Device) matrices are an older type of sensor, characterised by high image quality and good colour reproduction. Their disadvantages are higher power consumption and slower operation compared to newer solutions. Cameras using a CCD matrix include, for example, the Leica M9, Nikon D3X, Kodak DCS Pro SLR/c, Nikon D3 or the professional PhaseOne P65+.
CMOS Matrix
The most common matrix type is the CMOS (Complementary Metal-Oxide Semiconductor). It is characterised by low power consumption, fast operation and lower production costs. CMOS matrices match and often exceed the quality of older CCD matrices. Cameras with CMOS sensors include the Canon R5 (45MP), Sony A7R V (61MP), Nikon Z9 (45.7MP), Fujifilm GFX 100S (102MP) or Sony A1 (50MP).
Sensor Sizes
Main Sensor Formats:
- Full Frame (full frame) – size 36x24mm
- APS-C – approximately 23.6×15.7mm (Canon 22.2×14.8mm)
- Micro 4/3 – 17.3x13mm
- 1 inch – 13.2×8.8mm
- Smartphone matrices – typically under 1 inch
The size of the sensor has a key impact on image quality, especially in low light. A larger camera sensor means larger pixels, which can collect more light.
Key Sensor Characteristics
Key Features Affecting Image Quality:
- Resolution
- Single pixel size
- Dynamic range
- ISO sensitivity
- Colour depth
Together, these parameters determine the capabilities of the sensor and the quality of the images obtained.
The Sensor in SLR and Mirrorless Cameras
In SLR cameras, the sensor is protected by a movable mirror that lifts only when the image is taken. In mirrorless, the sensor is constantly exposed, which in theory can increase the risk of dirt, but allows for better real-time exposure control.
Mirrorless cameras offer advanced features due to the continuous readout of the sensor, such as exposure preview or advanced phase detection autofocus directly on the sensor. In SLRs, the sensor is not involved in the focusing process, which is done by a separate AF module.
Megapixels – Is More Better?
Megapixels define the resolution of the sensor – one megapixel is one million pixels. Today’s sensors offer resolutions from 20 to even 100 megapixels. However, the number of megapixels alone does not determine the image quality.
What is crucial is the size of the individual pixel. On a sensor of the same size, more megapixels means smaller pixels, which can result in more noise and poorer quality in low light. For most applications, a image sensor of 24-26MP offers the optimum compromise between resolution and image quality.
Sensor Life
The average life of the sensor is around 100,000 – 200,000 shutter releases, although many cameras exceed these figures. Professional models are often tested to 300,000 – 500,000 triggers.
The camera sensor itself rarely wears out – more often the camera mechanics fail. However, it is worth bearing in mind that intensive use in high temperatures or in bright sunlight can shorten the life of the sensor.
Does Sensor Size Still Matter?
Definitely yes. Despite advances in technology, the physics remain the same – a larger camera sensor can collect more light. This translates into better quality in low light, a wider dynamic range and a shallower depth of field. Larger sensors also provide better detail and lower noise.
Key Benefits of a Larger Sensor:
- Better quality in low light
- Larger dynamic range
- Shallower depth of field
- Better reproduction of details
- Lower noise level
Modern algorithms and advanced image processing in small sensors (e.g. in smartphones) can partially compensate for the differences, but cannot completely offset the advantage of larger sensors.
FAQ
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What is a camera sensor?
A camera sensor is the core component of a digital camera that converts light into digital signals. This digital sensor is the electronic equivalent of film in analog cameras and largely determines the camera’s image quality.
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What does an image sensor do?
The image sensor is responsible for converting light into digital images. It affects image quality, light sensitivity (ISO), dynamic range, and detail accuracy. Its quality is crucial for performance in low-light conditions.
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Does a digital sensor wear out?
Yes, a digital sensor can wear out over time. Main factors include the number of photos taken, exposure to strong light, and operating temperature. Typical lifespan is several hundred thousand shots, depending on usage conditions.
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How much does a new camera sensor cost?
A new camera sensor costs between $200 and $2000, depending on the camera model and sensor type. For older or budget cameras, sensor replacement often exceeds the value of the camera itself.
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How long does a digital sensor last?
A high-quality camera sensor should last for 150,000-300,000 shots. Professional cameras can reach up to 500,000 shots. The actual durability depends on usage conditions and equipment quality.
