[Article] cellphones and photography
I create this small text for a Brazilian Android Forum, called BrasilDroid, so I would put here in XDA too.
It is about the quality of our cellphones cameras and the quality of them.
A lot of definitions :
What is Photography ?
Literaly is write with light. The term is derived from Greek. photos(light) and graphos (drawing). So, the basic premise for take a picture is... Light!
What we need to take a photo?
For take a picture we need a camera with lens and film, that in digital photography is the camera sensor.
Pixel and Resolution
If we make a enlarge expansion in a photo we see various square points that make the image, this points are called Pixel. This is the minor measure that we have in our photos.
The photo resolution are directy connected to the Pixel. In a photo that have dimensions of 1920x1080 your resolution is 2,736,800 px or 2.1mpx.
Roughly, resolution is the photo area.
Quality vs Pixel
Many peoples confuse the camera quality with the amount of megapixel available.
But, quality not linked with quantity.
The Camera quality is linked direct to height of sensor and how the sensor handles the lack of light.
When we pont our camera for the scene and shoot a "curten" open and leave the sensor exposed to light. In this moment the sensor catch the light. Immediately after the "curten" close and the image is recorded.
While the obturator(the name of "curten") is open the sensor is capturing the light, so, smaller the area for capture minus details can be captured and more digital interference need to be used to create the image.
Let us consider two sensors:
Sensor 1 - 7x5mm.
Sensor 2 - 20x14mm.
These sensors be in two diferents cameras with 5mpx of resolution.
When we take a photo in 1920x1080 (Full HD) the sensor try capture the light of all scene usin 2.1 milions of points.
In First Sensor the pixel be very close, the area is smaller, making the size of these pixel be small, soon, the amount of detail that each of these pixels will be store are small.
In Second Sensor the pixels be more separated, the area is bigger, the pixels can capture mor information of the light.
The final image will be the same resolution in each sensors, but, the sensor two store more information. Considering the size of this sensors, Sensor two will store three times more information.
In other words, a small sensor need perform a big effort for store all information, are many pixels in a small area. This makes the camera need interfere in capture, generating small points between the pixels. In these moment we have other problem ... Grain...
So, for what serve the pixel ?
The more megapixel used in a photo greater be your dimension, so, more we can enlarge the picture keeping the proportion without loose information.
Why the photos look better on cellphone than on the computer?
That we see in screen of cell is basically a photo in a lower resolution than the real resolution, these lower resolution hide photos imperfections and some LCDs can make a bigger shine or contrast in the photos, like the AMOLED.
How to take better photos with cell ?
1 - Don't use the max megapixel
If you are shoot with cell, certainly, be a big image don't is your objective, so, you can take photos in small resolution. In Cell with 5.0mpx take a picture with 3.2mpx only bring gain...
2 - ISO
If the camera have manual ISO, try to use the lower ISO number, the higher ISO more digital inteference, and more grain...
But, the low ISO makes the scene need more light.
3 - Prefer shooting statics objects or don't shake
Most of cellphones don't allows the manual configuration of Obturator Speed. The camera software try to choice the better speed for the scene.
The phone try balance the speed with ISO and aperture, many times the speed is going down. And slow speed is synonymous of blur photo.
How to get around this? If possible, increase the ISO or increase the exposure compensation. And let the phone as still as possible.
4 - Using flash
Flash, very polemic, but, in cell cameras can be a great ally.
When use the flash your light make that the scene freeze, reducing very much the slow speed problem.
Obvious, xeon flash is better than Led.
5 - Modify the pr proportion
Case the camera be proportion adjust try choice the best of each photo.
Proportion 4:3 = 1.333
Proportion 3:2 = 1.5
Proportion 16:9 = 1.77
To calculate the proportion just divide the bigger side by smaller.
Para calcular a proporção é só dividir o lado maior pelo lado menor.
A Photo with 2048x1536 px be : 2048 / 1536 ~= 1.333
So, the resolution 2048x1536 have proportion 4:3.
To improve the photos working with the proportion the best way is using photo's editors.
Size of Sensors:
Digital Cameras :
Iphone and S3
They noted that the lower sensor of a digital camera 1/2.5 (0.4) is ~ 25% higher than the sensor of Galaxy S3 1/3.2 (0.31)?
Guys, it is clear that we can take great pictures with our cell phones, however, the limitation of the hardware and the sensor will always do that to that quality is not expected.
After all that, you imagine how absurd it is to have a mobile phone with 41mpx resolution?
A decent camera, that resolution costs over $ 20,000 and has a huge sensor, called medium format!
I propose a challenge. I take two pictures with my Ace 2. One with 5.0mpx and other with 3.2mpx. Both are in the ratio 4:3 with 100% Crop.
which of the photos was made with 5.0mpx and what was done with 3.2mpx?
Photo one :
That is, questions, suggestions ... and let the discussion!