First, what is noise?
The noise of an auto focus camera refers to the rough part of the image generated by the CCD (CMOS) receiving the light as a received signal during the output process. These rough parts are small rough spots, so they are called “noise.”
Integrated camera noise
In addition, there is a thing called bad point, many people are easy to “noise” and “bad point” confused. When your camera is in the same parameter conditions, the rough spots in the photos taken are always in the same position, that means that the camera has bad spots. However, the rough points in the photos taken are not in the same position, so it is the noise generated during use.
Second, the cause of noise
CCD (CMOS) has the problem of thermal stability, that is, the quality of imaging has a certain relationship with temperature. If your camera temperature increases, then the noise signal will become stronger, and it will form some specks on the picture, which is what we call noise.
Today’s camera manufacturers pay great attention to the control of noise, so there is a noise reduction function. However, noise can not be completely overcome, because it is related to speed (ISO), exposure time, camera temperature and other factors, it is difficult to completely overcome.
① Long exposure produces noise
The auto focus camera records image information through a photosensitive element, which requires electricity to work, and electricity must generate heat.
In addition, the sensor will also be affected by its own temperature during operation, so when the temperature of the sensor rises, some noise will be generated, that is, we often say “thermal noise”.
When we shoot for a long exposure, the sensor will work longer; The temperature of the sensor will also rise higher, resulting in a very noticeable noise.
To put it bluntly: the reason why long exposure produces noise is because the temperature of the sensor increases.
② High sensitivity produces noise
Why high sensitivity will produce noise, this problem is very broad, I give an example to let you simply do a simple understanding.
We adjust the speed of the camera (ISO) is to adjust the CCD signal processing, due to a large amount of increase, reduce the signal to noise ratio of the output signal, noise will of course appear. To put it simply, as the speed increases, the camera sensor will get more noise, which will produce more noise.
Just like when you listen to music on a stereo, you turn the volume down and you basically don’t hear the noise, but if you turn the volume up and you listen carefully you hear the noise. The camera speed increases the noise and the sound volume increases the noise principle is similar.
Camera noise reduction function comparison
③ Who is more serious about the noise generated by long exposure or the noise generated by high sensitivity?
Both high sensitivity and long exposure will produce noise, but in the normal exposure range, the noise caused by high sensitivity is more obvious.
SONY FCB-9500 series HD camera module has high sensitivity, so the noise generated during shooting is relatively obvious, but this series of cameras has 2D/3D noise reduction function, which can effectively reduce the noise and visual noise in the image, improve image quality and clarity.
Third, the adverse impact of noise
First, the effect of noise on image sharpness is obvious. Noise causes the image to become blurry, losing detail and edge sharpness. Especially in low-light conditions, the problem of noise is more obvious, which poses a challenge for shooting scenes at night, indoors, or in other low-light environments.
Secondly, noise also affects the image’s ability to display detail. In high-contrast scenes, noise can cause some fine details to be obscured or blurred, making the image lose its sense of layer and texture. This is especially important for photography tasks that require capturing detail and texture.
In addition, noise will also affect the color reproduction of the image. Noise may introduce color bias or affect color smoothness, making the color performance of the image less realistic and vivid. This is especially important for scenes where the true color of an object needs to be accurately reproduced.
FCB-EV9500M with MIPI network interface board
Four, noise reduction skills
As technology continues to evolve, camera manufacturers have taken a number of steps to reduce noise issues.
First, improving the quality and performance of image sensors is key. Modern cameras feature larger sensor sizes and a higher number of pixels, which can increase light capture and reduce noise issues.
Secondly, the use of advanced image processing technology, such as noise reduction algorithm and image smoothing processing, can effectively reduce the impact of noise. In addition, for some high-end cameras, it is also equipped with a special noise reduction chip or noise filter to further improve the image quality.
SONY auto focus cameras have multi-step noise reduction functions since the HD series, especially the 4K Ultra HD series and the 9500 series, which not only uses a larger sensor size, but also has 2D, 3D, 2D/3D three noise reduction options, which can effectively reduce noise and greatly improve the clarity of the image, the ability to display details and color restoration.