NoasArcAngel
Wise Old Owl
I read Vickybat's truly awesome explanation of DSLR technology and i was impressed, but i wanted to generalize camera technology for all. Since most of optics part is covered in Vickybat's guide, ill start with "tech" only and in very layman terms.
A . Sensor :
In digital cameras nowadays digital sensors are used to convert what you see on your screen to an image in digital format.
There are 2 types of sensors : CCD and CMOS
CCD : Charge Coupled Device, developed in 1969 by AT&T Bell Labs. The main R&D for CCD has been done by Fairchild Semiconductor Labs and mass production in later years by SONY. So if you buy a camera / video cam not made by SONY dont be surprised if its sensor is made by SONY.
CCD sensors are not only used in optics i.e. cameras but also medical applications.
CMOS : Complementary Metal Oxide Semiconductor, developed somewhere between 1964-1967 patent was later filed by Frank Wallas for CMOS in 1967. CMOS technology has not only been highly successful in optics but also in computers and analog RF.
Thus CCD / CMOS are 2 different technologies which have been adpated and remodified for optics use.
The battle between the Sensors has been going on since the past 10 years since digital cameras were introduced and especially DSLR became all the rage.
Which is better? which is not ? before i answer this question i just want to list these points :
1. CCD and CMOS are almost equally old technologies
2. Due to heavy R&D in CCD sensors these are much "mature" it has been around for a long time because of popularity of CCD sensors.
3. Image quality increases with sensor size. This is the rule of thumb.
Each technology has it advantages / disadvantages and exceptions which have been discussed later.
ADVANTAGE ( CCD over CMOS ):
1. simpler circuits, because CCD is a analog technology the requirement for circuit on sensor is much less. what this means is that ccd sensors can go through huge amounts of wear and tear (this number is in millions of hours) before effects of decrease in image quality show.
2. CCD sensors tend to have a better Dynamic Range. ( google for dynamic range explained )
3. The ability to stop and start exposure arbitrarily is very good in CCD sensors, meaning all those low exposure photos come brilliantly in CCD
4. CCD sensors based cameras with CCD sensors require additional circuits in the camera to stop image blooming.
ADVANTAGE ( CMOS over CCD )
1. very fast because almost all of the camera funtions are built on the CMOS sensor. ( results in shorter bootup, faster image capture and storage )
2. CMOS sensors are very "responsive" what this means is that the amount of electrical energy the sensor is able to relay to the camera per unit of optical energy it receives. What this means is that basically CMOS sensors use less energy and are more efficient.
3. CMOS sensors are immune to bloom by birth
4. Cheaper to manufacture, because of the nature of the design of the sensor these are cheaper to manufacture and have higher rate of production
Hence the difference between the 2 sensors technologies may seem a lot, but because of development in both of them they are on at par with each other.
Some people say the CCD sensors have less noise than CMOS ..... This statement is not 100% correct.
only when circuits are cooled and the output is slowed to such an extent that the noise can be reduced, only in this case ccd sensors can produce very accurate images with very less noise.
B. A simple comparison of camera sensor size, dont take this image as the size of the sensor because of the screen resolution this may change so the best thing to do is to take out that old ruler and pencil and make this on a piece of paper to see the difference yourself.
*www.creativevideo.co.uk/images/uploaded/sensor_table.gif
camera sensor size explained :
1. standard 1/2" sensor which is used in P&S cameras,
2. 4/3" or micro-four thirds as it is known ( system developed by olympus and panasonic )
3. the 1.6x crop factor is the canon DSLR sensor [ APS-C ]
4. the 1.5x crop factor is the nikon DSLR sensor
How does sensor size affect you ?
Sensor size is a very good way to differentiate between the quality of the image produced by the camera. Instead of going hunting for sample images on the internet or borrowing a camera, a sensor size will be able to give you a broad idea of the image quality.
The size of the sensor used in a camera directly affects the quality of the image because larger the sensor, more is the light which can fall on it and hence higher is the amount of detail which can be captured. ( this statement is not 100% true because image quality also depends on microlenses but by and large it is the rule of thumb. )
C. HD Video Recording and Bitrates Explained :
Nowadays you go to the market and almost every handheld digicam is offering " HD Video Recording " . But there is a camera for 5,000 also and one for 50,000 also which one is better and why ?
1. HD Video Resolution :
Many cameras may state " HD Video recording " and some may state " FULL HD Video recording " the difference is in the recording resolution.
Here is a list of the major commonly found recording resolutions.
* i will not be adding i/p at the end of resolution and will explain that separately.
a. Semi-HD (1280x720)
60fps
50fps
30fps
b. Full-HD(1920x1080)
60fps
50fps
30 fps
24 fps
fps = frames / second your camera records. Higher the fps smoother the video. Commercial movies are shot at 24 fps.
What does i/p at the end of the resolution denote ?
i - interlaced
p- progressive
the main difference between the 2 terms in layman language is that the interlaced record mode doubles the frames without increasing record size i.e. for a same video shot by 720i and 720p the 720p will take more storage space and will have higher bitrate than the 720i
* a special feature of progressive scanning is that the videos shot with this mode allow for still photographs / frames to be extracted from the video as they are.
A . Sensor :
In digital cameras nowadays digital sensors are used to convert what you see on your screen to an image in digital format.
There are 2 types of sensors : CCD and CMOS
CCD : Charge Coupled Device, developed in 1969 by AT&T Bell Labs. The main R&D for CCD has been done by Fairchild Semiconductor Labs and mass production in later years by SONY. So if you buy a camera / video cam not made by SONY dont be surprised if its sensor is made by SONY.
CCD sensors are not only used in optics i.e. cameras but also medical applications.
CMOS : Complementary Metal Oxide Semiconductor, developed somewhere between 1964-1967 patent was later filed by Frank Wallas for CMOS in 1967. CMOS technology has not only been highly successful in optics but also in computers and analog RF.
Thus CCD / CMOS are 2 different technologies which have been adpated and remodified for optics use.
The battle between the Sensors has been going on since the past 10 years since digital cameras were introduced and especially DSLR became all the rage.
Which is better? which is not ? before i answer this question i just want to list these points :
1. CCD and CMOS are almost equally old technologies
2. Due to heavy R&D in CCD sensors these are much "mature" it has been around for a long time because of popularity of CCD sensors.
3. Image quality increases with sensor size. This is the rule of thumb.
Each technology has it advantages / disadvantages and exceptions which have been discussed later.
ADVANTAGE ( CCD over CMOS ):
1. simpler circuits, because CCD is a analog technology the requirement for circuit on sensor is much less. what this means is that ccd sensors can go through huge amounts of wear and tear (this number is in millions of hours) before effects of decrease in image quality show.
2. CCD sensors tend to have a better Dynamic Range. ( google for dynamic range explained )
3. The ability to stop and start exposure arbitrarily is very good in CCD sensors, meaning all those low exposure photos come brilliantly in CCD
4. CCD sensors based cameras with CCD sensors require additional circuits in the camera to stop image blooming.
ADVANTAGE ( CMOS over CCD )
1. very fast because almost all of the camera funtions are built on the CMOS sensor. ( results in shorter bootup, faster image capture and storage )
2. CMOS sensors are very "responsive" what this means is that the amount of electrical energy the sensor is able to relay to the camera per unit of optical energy it receives. What this means is that basically CMOS sensors use less energy and are more efficient.
3. CMOS sensors are immune to bloom by birth
4. Cheaper to manufacture, because of the nature of the design of the sensor these are cheaper to manufacture and have higher rate of production
Hence the difference between the 2 sensors technologies may seem a lot, but because of development in both of them they are on at par with each other.
Some people say the CCD sensors have less noise than CMOS ..... This statement is not 100% correct.
only when circuits are cooled and the output is slowed to such an extent that the noise can be reduced, only in this case ccd sensors can produce very accurate images with very less noise.
B. A simple comparison of camera sensor size, dont take this image as the size of the sensor because of the screen resolution this may change so the best thing to do is to take out that old ruler and pencil and make this on a piece of paper to see the difference yourself.
*www.creativevideo.co.uk/images/uploaded/sensor_table.gif
camera sensor size explained :
1. standard 1/2" sensor which is used in P&S cameras,
2. 4/3" or micro-four thirds as it is known ( system developed by olympus and panasonic )
3. the 1.6x crop factor is the canon DSLR sensor [ APS-C ]
4. the 1.5x crop factor is the nikon DSLR sensor
How does sensor size affect you ?
Sensor size is a very good way to differentiate between the quality of the image produced by the camera. Instead of going hunting for sample images on the internet or borrowing a camera, a sensor size will be able to give you a broad idea of the image quality.
The size of the sensor used in a camera directly affects the quality of the image because larger the sensor, more is the light which can fall on it and hence higher is the amount of detail which can be captured. ( this statement is not 100% true because image quality also depends on microlenses but by and large it is the rule of thumb. )
C. HD Video Recording and Bitrates Explained :
Nowadays you go to the market and almost every handheld digicam is offering " HD Video Recording " . But there is a camera for 5,000 also and one for 50,000 also which one is better and why ?
1. HD Video Resolution :
Many cameras may state " HD Video recording " and some may state " FULL HD Video recording " the difference is in the recording resolution.
Here is a list of the major commonly found recording resolutions.
* i will not be adding i/p at the end of resolution and will explain that separately.
a. Semi-HD (1280x720)
60fps
50fps
30fps
b. Full-HD(1920x1080)
60fps
50fps
30 fps
24 fps
fps = frames / second your camera records. Higher the fps smoother the video. Commercial movies are shot at 24 fps.
What does i/p at the end of the resolution denote ?
i - interlaced
p- progressive
the main difference between the 2 terms in layman language is that the interlaced record mode doubles the frames without increasing record size i.e. for a same video shot by 720i and 720p the 720p will take more storage space and will have higher bitrate than the 720i
* a special feature of progressive scanning is that the videos shot with this mode allow for still photographs / frames to be extracted from the video as they are.
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