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How smartphone cameras work

The fact that people take a lot of photos on their smartphone is nothing new. In fact,many manufacturers now make phones which emphasize the camera as the main selling point of the phone. The Infinix Zero 4,Camon CX,HOT S,many phones from many manufacturers emphasize on taking great shots. But many people do not know how these cameras work. So,I'll explain.
There are six basic steps in taking photos on a smartphone camera. They are:
1. The user (or smartphone) focuses on the object.
2. Light enters into the lens.(light is everything on photography)
3. The arpeture controls how much light enters into the lens.
4. The shutter determines how long the sensor is exposed to light
5. The sensor captures the image
6. Post processing takes place in the software of the phone. There may also be some noise reduction.
Since most of the machines that do this are relatively simple machines,they all follow the laws of physics.
Now,in smartphones,some problems will arise. These problems are due to the fact that the arpeture,sensor and lens are all quite small. This leads to inefficient intake of light into the camera as a whole,leading to images not comparable to DSLRs.


So,then"What Makes A Good Photo?"
The trick is quite simple. Long exposure times,little ISOs in daylight and a fast shutter speed all help photos cone out nice. Luckily,all the phones mentioned above(less the CX) have professional modes that allow you to adjust all the above named. Fin.

See also: Samsung Galaxy S8 Review!


To take a photo,your smartphone needs to focus on the subject of the photo. This is really very important.
So,there are many ways of Smartphones focusing. Let's talk about that.
1. Phase Detect Autofocus
It works by using photo diodes across the sensor to measure differences in phase along the sensor and then moves the focusing element into the lens,bringing the object into focus.
The short form is PDAF,as you may have seen on some tech sites. For the sake of simplicity,I won't go into detail on this.



2. Dual Pixel Focus
This is a popular technology used on DSLRs,but it's quite new to smartphones. It is a form of PDAF that uses a far greater number of focus points along the sensor than PDAF. Think of it like this:
Instead of having pixels dedicated to focus,each pixel comprises of photodiodes that can compare subtle differences in how much light is reaching the opposite sides of the sensor.
Like this ,the amount of time spent in focusing is greatly reduced over PDAF,leading to lightning fast focus speeds.

See Also:HTC U11 vs Galaxy S8?



All this talk about arpeture,ISO,and lens makes this topic quite a confusing one. We'll take it not by bit.
What's In A lens?
For this part,we'll have to start with the explanation of focal length. So,what is a focal length?
It refers to the equivalent angle of view to the 35mm full frame standard. Now,while a phone camera can't have such a long focal length, listing it on the spec sheet means that the captured image would have roughly the same magnification as a full frame camera would with a 35mm lens. Therefore,"the longer the focal length,the more zoomed in a photo taken would be".
Most human eyes have a focal length of 55mm,so a photo taken with a lens having thaf focal length would look exactly the way you saw it. On summary,higher focal lengths,the photo looks zoomed in and vice versa.


Now to the arpeture
This is defined as a mechanism that restricts how much light enters the sensor and thus controls depth of field.
Wide open arpetures are greatly desired in photography,because they let in lots of light. Ironically,the smaller the f stop value,the larger the arpeture. Funny.
So,why that? It's because you're reading a mathematically notation. This means a ratio of the focal length divided by the arpeture opening. Simply focal length/arpeture size.
Courtesy:Android Authority

Next up is the electronic shutter
Electronic Shutter
Now shutters are next on the line. Actually,the speed at which the shutter opens and closes. A very fast speed would lead to underexposed images,while having it very slow leads to blurry photos.
Much like the aperture, shutter speed is listed out by “stops,” or settings that mark an increase or decrease in light gathering by 2x." A 1/30th second exposure is a full stop brighter than a 1/60th sec. exposure, and so on. Because the main variable you’re changing here is the time the sensor is recording the image, the pitfalls of choosing the wrong exposure here are all related to recording an image for too long or too short. For example, a slow shutter speed may result in motion blur, while a fast shutter speed will seemingly stop action in its tracks."(culled from Android Authority)



The number of megapixels is important also. Unfortunately,in the comparison of smartphone cameras, most people tend to like more megapixels over all the above named. The actual fact is "more megapixels,more problems". I'll explain.
Nowadays,Camera sensors are just really an array of even tinier camera sensors. But the number of megapixels in a sensor varies inversely as its ability to take in light. So therefore," the more megapixels, the less light is able to get into the sensor.". 
But,if you are able to make the individual pixels larger than regular pixels,you can collect more light even if the overall sensor isnt as big as it should be. 
 there is a benefit to increasing resolution a little bit. The Nyquist Theorem teaches us that an image will look substantially better if we record it at twice the maximum dimensions of our intended medium. With that in mind, a 5×7″ photo in print quality (300 DPI) would need to be shot at 3000 x 4200 pixels for best results, or about 12MP. Sound familiar? This is one of the many reasons why Apple and Google seem to have settled on the 12MP sensor: it’s enough resolution to oversample most common photo sizes, but low-res enough to manage the shortcomings of a small sensor. Fin.


Lastly,after the shot is taken,the software would have to compensate for the hardware's mistakes with post processing. This is the removal of digital noise and the restoration of shadows and dynamic range. The Google Pixel does this efficiently.


So there! That's all you need to know about how a smartphone camera works. Comments would be highly appreciated. Thanks for stopping by.

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