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Types of photo sensors and their characteristics

There are different types of photo sensors and it is essential to know them before buying a camera. In fact, depending on the characteristics of each one, it will allow you to obtain (or not) the photos you are looking for, while making the most of the lenses you have at home or that you plan to acquire in the long term.

Photo sensors

The first film cameras projected the photos onto film or reels, where the light was printed on this format and you couldn’t work quickly. With the arrival of digital cameras, films were no longer necessary since these new devices included a sensor where the light was reflected and therefore, our image too.

The sensor is the most sensitive part of the camera and probably the most important too. Rectangular in shape for most of them, composed of a large number of photosensitive cells of tiny size, whose function is to capture light. Each of these cells has a photodiode that converts light that reaches the lens into electricity. Electricity which in turn turns into information in the processor of our equipment. The more cells the photo sensors have, the more they will be able to capture and process light and information.

Each of these cells corresponds to the better known term of pixel. So if the camera is made up of 23 Mpx, we can say that it has 23 million photosensitive cells.

As they are very sensitive parts, the photo sensors must be protected at all times and be in contact with the outside as little as possible. Their cleaning will also be essential for quality information collected and therefore, for very clear photos too.

Types of photo sensors

Once we have located the sensor of the device, it remains to know their different types.

Full Frame or full frame sensor

These photo sensors are those normally used on professional cameras. It is the largest sensor and therefore has the largest number of light-sensitive cells. 36 x 24 mm, so it can capture the most information of the scene. When we think of Full Frame sensors, we imagine that they go with large and heavy devices, but this is no longer the case today.

The absence of a mirror and renovated constructions have noticeably reduced the sizes of the large cameras, thus going one of the big disadvantages of acquiring a Full Frame sensor camera.

APS-C sensor

These photo sensors are the most common. The APS-C sensor is present in most cameras on the market. Its manufacture is quick and less expensive, resulting in a drastic price reduction. It is 22.2 x 14.8 mm on Canon cameras, for 23.6 x 15.7 mm on Sony, Nikon and Pentax cameras.

The fact that this type of sensor has fewer photosensitive cells does not mean that it is not capable of providing spectacular results. But you still have to take into account the focal length of the lenses that you will attach to your work equipment. When talking about an APS-C sensor and an 18-55mm standard focal length lens, i.e. the lens usually included in camera kits, the actual focal length will not be 18mm but very high, at least 27 mm. And this will apply to all lenses.

In other words, if you want to work with a 14mm or 15mm wide-angle lens, you’ll need to purchase a lens with a shorter focal length, such as an 11mm. While it will be of great use for astrophotography, bird or wildlife photography since when working with a telephoto lens, the focal length will be increased, so you will achieve first shots of scenes away from you. Chek for more lenses on

Other photo sensors

These two photo sensors are the most common, but there are many others, such as the Micro Four Thirds characteristic of Olympus and Panasonic cameras, which measures 17.3 x 13 mm, or the Foveon sensor, specific to Sigma cameras, from 20.7 x 13.8mm.

As for compact devices, note that there are three types of photo sensors: 7.6 x 5.7 mm, 7.18 x 5.32 mm and 5.76 x 4.29 mm. These are the most common but there are many more. Remember that the smaller they are, the less photosensitive cells they will have and they will therefore be able to gather less information from the scene that will present itself.

Types of sensor technology

Here is another factor to consider before choosing for one camera or another. The camera sensor is used to transform the light that reaches it into digital information, but there are different systems or technologies to carry out this conversion, the differences of which lie in the manufacturing process and the performance.

There are several types of sensors but we will look here at the two best known, those that equip most cameras on the market.

CCD sensor

The first to hit the market was the CCD sensor. It is currently the most expensive sensor to manufacture, it provides much slower image processing but it gives excellent results.

CMOS sensor

This type of sensor equips most of the cameras on the market because it is less expensive to manufacture, which gives much more affordable camera prices. The processing they offer is much faster, for results equivalent to those of CCD sensors.

And as if that were not enough, CMOS sensors consume less battery, an undeniable advantage over other sensors.

Other aspects to consider

As we have seen, whether you settle for a device with one sensor or another, this will have repercussions on the actual focal length that you will use on your photo shoots. And it will also directly affect the sharpness of your achievements. The more photosensitive cells there are, the more information will be obtained from each photo. But it’s not enough if we don’t use a lens that allows us to collect the greatest possible share of light, in other words with an aperture of type f/1.4 or f/1.8.

If, on the other hand, it is a low-light lens, with large defects that can reveal refractions and chromatic aberrations, and you are working with a full-frame sensor, then it is very likely that these defects there are reproduced on your final results.

The ISO sensitivity will also be a factor that will directly influence the sensor of your camera. The higher the ISO value, the more sensitive the sensor will be to light, which is especially useful for collecting light in the dark. But when this information is impossible to obtain due to the complete blackness of the area and therefore also on this photosensitive cell, this turns into noise. If possible, use low or medium ISO values ​​and you will avoid the appearance of this noise.


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