Terminology can be scary some times. So much technicality can repel us, right? But of the missions of this blog, if not the main one, is to spread photographic knowledge and to democratize photography among all of our readers.
A topic that is often put off due to its apparent complexity is the sensor one. That is false my friend. It is not at all a complex issue, in fact, it is quite the opposite. And even though it not bad to know some photography concepts, it turns out that the sensors is one key element in a camera.
In today’s article I will talk about this “vital organ” called sensor. If you are about to buy your next camera, it is necessary for you to know about the sensor. This way you will make a good selection. If you already have a camera, it is still worth knowing about the sensor within it.
What is a sensor?
It doesn’t matter whether it’s a SLR or a compact one, the sensor is the heart of our camera. Everything we do to capture a good picture, from the moment we frame the shot until the moment we take the picture are all actions and steps in order to achieve one goal: conducting the exterior light (the image) towards the sensor of the camera.
The sensor, as its name indicates, is a “sensitive” element inside our camera. It is it where the light is projected, drawing an image that represents what the camera sees. The sensor is to digital cameras what film was to analog cameras. The difference is that in analog cameras you needed to replace the film, while in digital cameras the sensor is fixed and it doesn’t need to be replaced. We can “project” on it as many pictures as we want since we already have the memory card to store the images.
What is the sensor of my camera made of?
If you are curious about what is in the sensor in your camera, don’t worry, you don’t need to turn it apart for you to know. That’s what I am here for 😉 . So your cameras sensor is somewhat a small chip made out of millions of light sensitive components called pixels. This millions of pixels always have to be in the dark, and as soon as they are exposed to light, they will capture it. And that’s why they are sensitive. Because they are able of capturing this light, we get the image.
Sensors can be classified according to their technology, and must surely the one in your camera belong to one of the following types:
- CCD and Super CCD
- CCD RGBE
- Foveon X3
Although in reality, the two most used or most popular sensors are the CCD and the CMOS. I don’t want to bore you with a series of technical specifications on each one of these formats because I think that they are not that relevant. What you really should know is that the CCD ones were the first ones to be used, but nowadays most of the cameras are using a CMOS sensor. And it is because it was discovered that this new technology called CMOS allowed the creation of less power hungry sensors, and that also allowed a faster image processing. In addition, it is much cheaper to manufacture a CMOS sensor rather than a CCD.
As for the picture quality, CCD had offered better image quality in the past, but over time, the CMOS has reached that same quality.
In sensors.. Does size matter?
Yes! It does matter, and it matters a lot. Whenever I go and buy a digital camera, be it SLR or compact, the first thing I look at is the sensor size. That will determine the quality of the camera, and therefore pictures.
In order not to embroil you with terminology and abstract explanations, I leave a list with the sizes of the most common sensors. They are ordered from largest to smallest. The rule I want you to always remember is: the bigger the sensor, the better.
- Full Frame Sensor, also known as a 35mm sensor. Dimensions: 36x24mm
- APS-H Sensor. Dimensions: 28,7x19mm
- APS-C Sensor (used in Nikon, Pentax and Sony). Dimensions: 23,6×15,7mm
- APS-C Sensor (used in Canon). Dimensions: 22,2×14,8mm
- Foveon Sensor (used in Sigma cameras). Dimensions: 20,7×13,8mm
- Micro Four Thirds Sensor. Dimensions: 17,3x13mm
- [… other smaller sensors…]
Update: Alvaro asks me if the size of the sensor comes specified in smaller cameras. In here I recommend the following: try to find out the size of the sensor on the camera box. If you can’t find it there, look for it on the store’s website. If you can’t find it there either, you need to search in specialized websites where all the camera’s features are shown. A good website for this matter is the very famous dpreview, where they analyze in detail any cameras and most of the time indicating the size of the sensor.
On the other hand, as for compact digital cameras, there tends to be 3 sizes which are the most widespread, and are the following from biggest to smallest.
- 1/1,7″ (7,6 x 5,7mm)
- 1/1,8″ (7,18 x 5,32 mm)
- 1/2,5″ (5,76 x 4,29 mm)
I hope this info comes handy.
Note: It is convenient for you to know that the sensor affects the quality of the picture and the len’s focal distance. When we buy an 18-55mm lens and we use it at 18mm, actually It is only 18mm if we have a 18mm Full Frame Sensor (the first one the above list, the big one. If the sensor is smaller, then the real focal distance won’t be 18mm but bigger. Maybe 27mm or somewhere around that. The smaller the sensor, the greater real focal distance we’ll get. This is a drawback if we are looking for a wide-angle picture, but is a real advantage if what we want is a huge tele-objective zoom. So with 200mm we’d get almost 200mm.
Other sensor’s features
I left this for the end because I think you will give it a bigger importance than it actually deserves, although, if we want to be fair I can’t exclude you from this article: the number of megapixels and the ISO sensitivity are also two important factors in a camera’s sensor. In theory, the more megapixels we have, the better quality picture we’ll get. Although it is not always like that, so do not rush to buy a camera just because of the number of megapixels it’s got. The other important factor to keep in mind is the ISO sensitivity. This indicator reveals the sensitivity of the senses towards light. For example, taking a picture at 200 ISO will capture twice as much light than it would at 10o ISO. Although it is known that the more ISO sensitivity, the more noise we will have in the picture. So beware.
This is all on the sensors topic. All you needed to know about sensors you know now. As usual, I hope you enjoy this article.
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