The terminology is scary, sometimes. So much technicality puts us off, right? But one of the missions of this blog, if not the main one, is to spread photographic knowledge and democratize photography among all its readers. A subject that is often pushed back due to its apparent complexity is the subject of photo camera sensors. Fake friend. It is not a complex issue at all, quite the opposite. And although it is not serious to ignore some concepts of photography, it turns out that the sensor is a key piece in a camera.
In this article today I am going to talk about this “vital organ” called a sensor. If you are about to buy your next camera, you need to know what the sensor is, so you will make a good choice. If you already have a camera, it is also convenient for you to find out about the sensor that it has inside.
What is the sensor?
It does not matter if it is reflex or compact, the sensor is the heart of our camera, the goal. Everything we do to capture a good photo, from the moment we frame it to the moment of shooting, are all actions and steps that pursue a single goal: to direct the light (the image) from outside towards the camera sensor.
The sensor, as its name suggests, is a “sensitive” element inside our camera, the thing on which light is projected, drawing an image that represents what our camera sees.
The sensor is for digital photo cameras like the film or reel that we used in analog photo cameras. The difference is that in analog cameras the film had to be changed while in digital cameras the sensor is fixed and does not need to be changed. We can «project» on it as many digital photos as we want, because to store the photo we already have the memory card.
camera with sensor in sight
What is my camera sensor made of?
If you’re curious to know what your camera’s sensor is made of, don’t worry, you don’t have to break it to find out. That’s what I’m here for 😉 Well, your camera sensor is a kind of small chip made up of millions of light-sensitive components, called pixels. Those millions of pixels have to be always in the dark, and as soon as they are exposed to light they capture it, so they are sensitive. Thanks to the fact that they capture that light, we obtain the image.
sensor technology
Sensors can be classified according to their technology, and the one in your camera probably belongs to one of the following types of sensors:
- CCD and Super CCD
- CCD RGBE
- CMOS
- Foveon-X3
Although in reality the 2 most widespread or popular types of sensors are the CCD and the CMOS.
I don’t want to mistreat you with a series of technical specifications about each of these formats, because I think they will be irrelevant to you. What you should know is that CCD-type sensors were the first to be used, but today most cameras are using CMOS sensors. Well, it was discovered that this new technology called CMOS allowed the creation of sensors that consumed much less battery and at the same time allowed much faster image processing. On the other hand, factories find it much cheaper to make a CMOS sensor than a CCD one.
In terms of image quality, in the past CCDs offered better image quality, but over time CMOS have already achieved that quality.
In the sensors. Does size matter?
Yes. It matters a lot. When I go to buy a digital camera, be it SLR or compact, almost the first thing I notice is the size of the sensor. He will determine the quality of the camera and therefore the quality of the photos.
In order not to confuse you with terminology and abstract explanations, I leave you below the list of the most common sensor sizes. They are ordered from largest to smallest. The rule I want you to remember forever is easy: the larger the sensor size, the better.
- Sensor full frame, Also known as a 35mm sensor. Dimensions: 36x24mm
- Sensor APS-H. Dimensions: 28.7x19mm
- Sensor APS-C (Used on Nikon, Pentax and Sony). Dimensions: 23.6×15.7mm
- Sensor APS-C (used in Canon). Dimensions: 22.2×14.8mm
- Sensor Foveon (used in Sigma cameras). Dimensions: 20.7×13.8mm
- Sensor Micro Four Thirds. Dimensions: 17.3x13mm
Update: Quite correctly, Álvaro asks me (in the comments below) if the size of the sensor is specified in compact cameras. Here I recommend the following: try to find out the size of the sensor in the camera box, if it does not come try to see it in the description of the camera on the store’s website (for example, Fnac.es), if it does not come there I recommend search on specialized websites where all the characteristics of the camera come. A good website for this effect is the famous dpreview where they analyze in detail any camera almost always indicating the size of its sensor.
On the other hand, in terms of compact digital camera sizes, there are usually 3 sizes that are the most widespread and that are the following, from largest to smallest:
- 1/1.7″ (7.6×5.7mm)
- 1/1.8″ (7.18 x 5.32mm)
- 1/2.5″ (5.76 x 4.29mm)
I hope this info is useful.
Note: You should know that the size of the sensor affects, in addition to the quality of the image, the focal length of the lens. When we buy an 18-55mm lens for example and use it at 18mm, it’s really only 18mm if we have a Full Frame Sensor (the first one on the list above, the big one). If the sensor is smaller then the actual focal length will not be 18mm but larger, maybe 27mm or something like that, and so on, the smaller the sensor, the longer the actual focal length we will get. This is a drawback if we are looking for a wide-angle photograph, but it is an advantage if what we want is a telephoto lens with a huge zoom. Well, with a 200mm we would get almost a real 300mm.
Sensor sizes
Other features of the sensors
I have left them for last because I think they are given more importance than they should be, however, if we want to be fair, I cannot exclude them from this article: the number of megapixels and ISO sensitivity are also two important factors in a camera sensor.
In theory, the more megapixels our sensor has, the better image quality we will obtain. This is not always absolute, but what affects the most is the size of the prints you are going to make, so do not rush into buying a camera just because it has a higher number of megapixels, although it is a factor to consider.
The other important factor is ISO sensitivity. This indicator reveals the degree of sensitivity of the sensor to light. For example, shooting a photo at ISO 200 will capture twice as much light as shooting it at ISO 100. Although it is known that the higher the ISO sensitivity, the more noise we will have in the photo, so be careful.
If you want to delve (much) more into the subject, in the following video David tells you about it much more extensively and in detail.
That’s it for the topic of sensors. Everything you need to know about sensors now you know.
As always, I hope you have enjoyed this article on camera sensors. If you find it useful and want to share what you’ve learned with other readers, please don’t hesitate to vote for it or recommend it on your favorite social network. I will be very grateful to you 😉