From Full-frame to Smartphone: Comparing the Most Important Camera Sensors

An image sensor is the central component on every digital camera and consists of millions of light-sensitive photodiodes that convert the incident light into electrical signals. These signals are then stored as pixels and form a digital image.

Sensor size has a direct impact on image quality, control over depth of field and the camera's ability to perform well in different lighting conditions. Larger sensors can capture more light, which leads to better results in low light conditions. They also offer greater detail and less image noise. Larger sensors can also achieve a shallower depth of field, which is particularly advantageous in portrait photography as the background can be blurred more easily.

In photography there are a variety of sensor sizes that differ in their performance, price and where they are used. Below you will find the most common sensor sizes used in modern digital cameras, including their advantages and disadvantages:

Full format, also known as 35 mm format, is derived from 35 mm film and measures 24 mm x 36 mm. Full-frame sensors are mainly found in expensive digital cameras.

Due to their larger surface area, full-frame sensors offer more space for pixels, which leads to better light sensitivity and excellent image quality, especially in low light conditions. The ISO value often does not need to be increased in low light conditions, which will minimise image noise.

Thanks to the high light intensity of the sensor, shorter exposure times are also possible, which facilitates blur free hand-held shots. In addition, full-frame sensors offer the largest possible image section, as a no crop factor influences the focal length.

The advantages of a full-frame camera are the image quality and light sensitivity. The disadvantages are their size, weight and the higher costs. In addition, high-quality camera lenses are required to utilise the full performance of the sensor, which can further increase the overall costs.

APS-C sensors, also known as DX sensors, are the next smallest sensors on a full-frame format and are often found in digital SLR and mirrorless cameras.

The size of an APS-C sensor varies depending on the brand, but it is typically around 22.3 mm x 14.9 mm with an aspect ratio of 3:2. Canon introduced the term APS-C, while Nikon uses the designation DX for the same format. Due to their smaller size, APS-C sensors have a crop factor of around 1.5 to 1.6. This means that the image section is reduced compared to full format and the effective focal length of the lenses is extended.

Although APS-C sensors can absorb less light than full-frame sensors, they still offer good image quality, which can be further improved with high-quality camera lenses. The crop factor can be perceived as a disadvantage in the wide-angle range, as the image section is smaller and therefore shorter focal lengths are required.

The advantages of APS-C sensors are their compactness and they are a lot lighter and cheaper in comparison to full-frame cameras. These characteristics make cameras with APS-C sensors particularly attractive for amateur photographers and those who prefer more practical camera accessories. In addition, the reduced image quality shouldn’t be regarded as a major disadvantage, as this can be compensated with high-quality camera lenses.

Four-Thirds sensors can be found in small digital SLR cameras and in mirrorless compact cameras. These are 30 to 40 per cent smaller than an APS-C sensor.

In addition to their sensor size, a standard Four-Thirds also defines the lens bayonet including the communication protocol, the imaging circle and the flange focal distance, which means that camera lenses from different manufacturers fit the same camera model. This is not easily possible with a DSRL with an APS-C sensor. Both Canon and Nikon use different standardised camera lens mounts.

The Micro-Four-Thirds (MFT) standard, which does not have a mirror and therefore has a smaller flange focal length. This makes MFT cameras more compact and lighter. Without a mirror and optical viewfinder, the subject is only shown on the display via Live View mode, which is less ideal in a bright environment.

One disadvantage of a Micro-Four-Thirds is the greater depth of field, which makes it more difficult to blur the background in portrait photography. The light intensity is also lower compared to a full format, but this can be partially improved with high-quality camera lenses. However, the slower autofocus remains a disadvantage, especially when taking pictures of moving objects.

The advantages of Micro Four Thirds cameras are their compactness and versatility. They offer good image quality in a handy format, which makes them ideal for travelling and everyday use.

Medium format sensors are larger than full format sensors and offer exceptionally high image quality and detail. Typical sizes are around 44x33 mm or larger. These sensors are commonly used in professional photo studios and on landscape photography cameras, where the highest resolution and dynamic range are required.

Due to their larger sensor, medium format sensors can capture more light, which leads to very good results in low light conditions. They also offer a shallower depth of field, which is an advantage for portrait shots as the background can be blurred more easily.

The disadvantages of cameras with medium format sensors are their size, weight and high costs. They tend to be larger and heavier than cameras with smaller sensors, and both the cameras and the associated lenses are significantly more expensive. Despite these disadvantages, medium format sensors offer unrivalled image quality, which is essential for certain professional applications.

1-inch sensors and smaller sensors can be found in many compact cameras and smartphones. They offer a good balance between image quality and compactness. A typical 1-inch sensor measures around 13.2 x 8.8 mm and delivers better results than even smaller sensors in most smartphones.

These very compact and lightweight cameras are ideal for snapshots in everyday life and when travelling. They offer acceptable image quality in good lighting conditions, but they have significantly improved in recent years. They are now more powerful thanks to new and better technology.

However, these sensors have limitations. In low light conditions and high ISO values, they tend to produce more image noise and less detail compared to larger sensors. Control over depth of field is also more limited, which can restrict your creativity.

Despite these disadvantages, cameras with 1-inch and smaller sensors, especially smartphones, are very popular due to their compactness and ease of use. They make it possible to take high-quality photos anytime and anywhere without having to carry a large camera kit.

There are some important factors to consider when choosing the right sensor for your camera. The sensor size directly influences the image quality, depth of field and light sensitivity. For example, cameras with full-frame sensors offer the best image quality and performance in low light conditions. However, they are larger, heavier and more expensive, but are ideal for portrait and landscape photography.

APS-C sensors offer a good balance between quality and cost and are therefore ideal for amateur photographers. Micro-Four-Thirds sensors, on the other hand, are compact and versatile, making them perfect for travelling and everyday use.

Medium format sensors offer the highest image quality and are therefore suitable for professional photo studios and landscape photography. However, they are expensive to purchase and are quite heavy. 1-inch and smaller sensors, including smartphone sensors, offer portability and ease of use, which makes them the ideal choice for going on holiday and everyday snapshots.

To find out which sensor size best suits you, it is important to try out different sensor sizes. Whether it's portrait shots with an impressive bokeh effect, breathtaking landscapes or fast paced sports photos. Therefore, choosing the right sensor can make a big difference, but it is also important to experiment with different options and gain your own experience to achieve the best results.