Mavik
01-11-2008, 05:28 PM
Was just reading up online about CCD's and noise handling and various items about newer cameras on full frames with ever increasing MP count for them.
Well, ST did mention that we hardly share anything here but let me try to recount my old days when working with CCD's and my research.
Basically when it comes to noise handling and ISO performance, I would like to just talk about how the CCD/CMOS sensor comes into affect.
Imagine a cropped sensor, both physically having the same dimensions but CCD A has 10MP and CCD B has 12MP. In terms of the physical area, CCD A would have 10M pixels on the CCD, and B would have 12M pixels. On the same surface area, that means the size of each individual pixel on CCD A would be larger compared to the B.
When you have a larger pixel or sensor, basically the amount of light that can enter it is more hence the less need to amplify the signal before it is processed. The less you need to amplify, the less noise you would amplify as well hence you would get less noise.
Why do you think full frame sensors have such good ISO performance because the size of the sensor themselves are already larger than the normal cropped sensors hence it is more sensitive and require less amplication of the signal.
When it comes to noise control, the manufacturer can play with the trade-offs between noise vs sharpness. Just think of it this way (this is done at the digital signal processing stage via EEPROM data), increasing the sharpness of the image would definitely be a good thing but that would mean making the noise extremely visible as well. I know that some manufacturers will definitely try to reduce the noise by sacrificing image clarity and I have actually done that before as well (back in the days when I configured settings for camcorders)
Anyway, just wanted to share some info about some bits and I hope I don't get flamed too much by it.
Well, ST did mention that we hardly share anything here but let me try to recount my old days when working with CCD's and my research.
Basically when it comes to noise handling and ISO performance, I would like to just talk about how the CCD/CMOS sensor comes into affect.
Imagine a cropped sensor, both physically having the same dimensions but CCD A has 10MP and CCD B has 12MP. In terms of the physical area, CCD A would have 10M pixels on the CCD, and B would have 12M pixels. On the same surface area, that means the size of each individual pixel on CCD A would be larger compared to the B.
When you have a larger pixel or sensor, basically the amount of light that can enter it is more hence the less need to amplify the signal before it is processed. The less you need to amplify, the less noise you would amplify as well hence you would get less noise.
Why do you think full frame sensors have such good ISO performance because the size of the sensor themselves are already larger than the normal cropped sensors hence it is more sensitive and require less amplication of the signal.
When it comes to noise control, the manufacturer can play with the trade-offs between noise vs sharpness. Just think of it this way (this is done at the digital signal processing stage via EEPROM data), increasing the sharpness of the image would definitely be a good thing but that would mean making the noise extremely visible as well. I know that some manufacturers will definitely try to reduce the noise by sacrificing image clarity and I have actually done that before as well (back in the days when I configured settings for camcorders)
Anyway, just wanted to share some info about some bits and I hope I don't get flamed too much by it.