Digital camera - when to use which sensor?

Before you buy a digital camera, you should inquire about the size of the sensor installed. The image sensor is the circuit board on which the phototransistors that process the incident light sit. Therefore, the image quality sometimes depends on the size of the sensor. In this article we explain exactly what you should pay attention to.

Digital camera: dependence on sensor and image quality

The sensor of a digital camera is a circuit board on which photo transistors are installed. The number of these transistors depends on the specified megapixels. So if you buy a camera with a resolution of 20 megapixels, there are 20 million transistors on the chip. This leads to the following circumstances:

• The more transistors installed on a sensor, the more light information your camera captures. This means that with large megapixels, more details are also shown in your images.
• At the same time, the size of the individual phototransistors depends on the size of the sensor. If you have a camera with a large full-frame sensor and a resolution of 20 megapixels, each individual transistor is larger than that of a smaller chip.
• The smaller a transistor is, the more sensitive it is to the incidence of light. With a small chip with many photo transistors, as is the case with cheap digital cameras, there are therefore many image errors. For example, pictures taken in the dark are affected by excessive picture noise.
• However, if you have a camera with a large sensor and the same megapixel specification, the transistors are larger and process less incorrect image information. However, if the chip is large and the resolution is very high, small transistors must also be installed and the same image errors occur as with smaller sensors.

Choosing the right digital camera: Optimal choice of sensor and resolution

In order to take photos where there are only a few image defects and at the same time enough details, you have to compromise between sensor size and resolution:

• Generally, a resolution of more than 10 to 12 megapixels is not necessary for private use. A higher resolution usually only leads to more image errors and ruins your recordings. An example of a camera with exactly this problem is the Canon IXUS 170.
• In addition, sensors are very expensive, which is why manufacturers like to use small sensors. The common sensor names are Micro Four Thirds for the smallest sensors, APS-C for medium-sized sensors and full-frame sensors.
• If you are looking for a good compromise, you should choose an APS-C and a resolution between 10 and 20 megapixels. For advertising reasons, you will hardly find any cameras with a resolution below 20 megapixels. A camera that corresponds to this data is, for example, the Sony Alpha 5000 system camera.