What happens inside a camera, behind a single shutter sound that we hear.
'What’s a big deal in taking a photo. After all it’s just clicking.’
I have heard this sentence thousand times, if not less. I don’t know why people think that the photographer just have to click the button to take the photo. May be because they don’t know which and how many processes take place inside a camera to take a single photo. So let’s get detailed information about this.
Following are the parts of camera, which carry out various processes in the camera, starting from entry of light through lens, all the way up to storing the final image.
1. Lens
2. Mirror and prism (Only in case of DSLR camera)
3. Screen
4. Shutter mechanism
5. Sensor
6. Processor
7. Storage space
Now let’s see all of these points in detail.
1. LENS
Lens is nothing but a number of concave and convex glass elements, stacked together in various groups. Light passes through all the glass elements and reach to the sensor when the camera is on. The quality of photo depends upon quality of all these elements. Sometimes there may be a special chemical coating on some of the elements to maintain the quality of incoming light ray. All these elements are spaced and grouped in such a way that, they concentrate incoming light on sensor.
Now-a-days, there is provision of auto focus system inside the lens. Also some lenses have image stabilization systems built in, which helps in taking sharp photos even if there is slight hand movement while taking photograph. But construction of all lenses vary in the aspects like, size and number of glass elements, chemical coatings (if any), quality of glass elements, etc. That’s why the prizes of all the lenses are not same and vary from few dollars to thousands of dollars.
Below are the links of some classic lenses. If you want to see or buy those lenses, just check out the links.
2. MIRROR AND PRISM
Among all types of cameras, only DSLRs have mirror and prism assembly built into them. When the light enters camera body through lens, it gets reflected up from the mirror fixed at 45 degree angle. Then after that, that light is again reflected twice from inside of the prism and then it is allowed to come out of camera body from viewfinder. That’s why we can look from view finder and frame the photo.
But this system reflects incoming light without doing any processing on that. That’s why if there is less light in the surrounding, the view finder will be dark.
3. SCREEN
Except DSLR, in all other types of cameras we can see on screen, what’s going on the in front of camera. This helps in framing the shot and clicking the photo. Many cameras feature swiveling and rotating screens. Higher variants of cameras also have touch screen functionality.
If we want to take photos from unusual angles, then we can enable live view function on the screen and easily take the photo. Screen mainly has three functions as, showing camera settings, showing live view and taking photos (in case of touch screen).
4. SHUTTER MECHANISM
Shutter mechanism acts as a door to incoming light. It mainly has two parts namely, first curtain and second curtain. When we press a button these two shutters pass from up to down, in front of the sensor. Means at first the first curtain goes down exposing the sensor and after some specific set time (shutter speed, to be more specific), second curtain also comes down, now covering the sensor. In between these two movements, a photo is taken.
These movements of mirror mechanism and shutter curtains make the sound which we generally call as shutter sound.
5. SENSOR
Sensor is the SOUL of the camera. When the light coming through the lens falls on the sensor, that information is saved and converted to electronic signal, by the sensor. Sensor is made up of PIXELs. They are tiny units which capture photons. The size of whole sensor and it’s resolution in Mega pixels is dependent on the size of individual pixel and total number of pixels.
Consider two sensors (small and big) having same number of pixels. In small sensor, size of individual pixel is also small and thus it’s low light performance is bad. But in bigger sensor, size of individual pixel is bigger and thus it’s low light performance is good.
Generally in DSLR and mirror-less cameras, there are four types of sensor based on their size, as Micro four third sensor, Crop sensor, Full frame sensor and Medium format sensor. Ultimate point to remember is, the size of sensor directly derives quality of photos.
6.PROCESSOR
Image processor does processing on the information gathered by camera sensor. It decides, what changes are required to be made to collected data, in terms of brightness, contrast, colour, sharpness, etc. After this processing is done, we get final image in the format of JPEG or JPG.
So the camera with better processor produces better photos. But we have no control over this processing done on RAW data from sensor. That’s why sometimes camera’s algorithms and our vision about a photo, don’t match and we get a photo which is not according to our initial thoughts. The solution to this, is using RAW photo function in camera. Now 'what is a RAW photo and how and when to use it?' that we will see in some future post. But for now it is enough to only know that, RAW photo means the RAW or unprocessed data collected by the sensor, so that we can process it later in editing software, as per our taste and need.
Processor speed also plays an important role while using camera. Because we can take second photo only after first photo has been saved. In recent cameras, the processors are so fast, that we can take a burst of several images, continuously.
7. STORAGE SPACE
After the data from the sensor is processed and the photo is ready, it is then saved in the memory card. The memory cards also have many types based on their data reading and writing speed. With faster cards, camera can work faster.
Some higher end cameras feature dual memory card slots. This allows the user to save recorded data (photo or video) on two memory cards at the same time, so that if something bad happens, the user always has the backup ready.
Below are the links of some best memory cards. If you want to see or buy those for any use, just check out the links.
Now after all this, if the photo taking process is to be explained in short, it would be like as given below.
1. Light enters the camera through attached lens.
2. Then (in case of DSLR camera) light gets reflected from mirror and prism to allow user to see through view finder and frame the shot. In all other cameras types, this light directly falls on the sensor and user gets to see live digital preview in the view finder or on the screen.
3. After the framing/composing has been done, user clicks the button and shutter mechanism works to allow the light to fall on the sensor, for predefined time span (shutter speed).
4. After that, sensor records the data, converts it to digital electronic signal and sends it to image processor.
5. Processor analyses the incoming data and processes it according to predefined algorithm or settings.
6. After that, finally the processed photo or the RAW data (as the setting may be) is stored in the memory card, for further use.
When we take a photo, we only listen a specific 'clicking' sound. But behind that single sound, all these processes happen inside the camera, this should be considered as nothing but a technological miracle.
So after this point, don’t consider the photo taking process as JUST CLICKING A BUTTON. And if somebody says that to you, send them the link of this post, so that they also can get rid of their mis-understanding.
After all, nobody should live with a wrong perception. Isn’t it?
- Prasanna Joshi
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'CAMERA SENSOR'
The SOUL of the camera
Keep smiling & keep clicking.
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