You have your new camera and everything goes very well, until you start taking pictures in low light situations and you realize that a spice of granularity appears in the image that causes it to lose sharpness. That grain is digital noise.
What is digital noise
Noise is the headache of the digital age. There are different types of noise, but the most common are the luminance noise, caused by the lack of light, and the color noise, caused by the heating of the sensor which is best flight time drone .
A pixel is a color dot, and a set of pixels form an image. The noise appears when the color and light of some of those pixels are altered and that spoils them. If we enlarge a photograph to see it in more detail, we can see the altered pixels, especially in the darker areas.
How we can combat digital noise
We started with the first type of noise we mentioned, the noise of luminance.The first thing we have to take into account is the size of the camera sensor. Here’s why:
- The sensor is formed by a surface of cells that react to contact with the light entering through the optics of the camera.
- Each cell has light detectors, called photodiodes, which are responsible for converting light into electrical signal.
- And that electrical signal becomes an image that is stored in the memory of the camera.
The problem is less frequent if the sensor of the camera is larger, because it has more capacity to capture the light and so you do not have to “invent” so much data. In addition, the pixels have more space to each other, and the higher the pixel density, the higher the likelihood of noise.
We have already spoken in other vlogs of the different types of sensors, from the medium format to the tiny sensors of some compact.The second thing that you have to take into account to have no noise in the image is the use of low ISOS, as long as the image is well exposed. The more we raise the ISO value, the more we amplify the signal and the more noise we will have.
Before raising the ISO you can adjust the aperture of the diaphragm.
In photography we have more margin and we can use the shutter speed and the diaphragm at the same time. But in video, the shutter speed is limited to 1/30, once we have reached the minimum speed we can resort to opening the diaphragm before resorting to ISO. You can also find a place where you can take advantage of natural light or, if you have artificial light, regulate the intensity.
Depending on the objective you can get more or less opening. We recommend those that allow you more. Today, for example, we recorded with a 16-28 mm Tokina that lets us open the diaphragm up to 3 in all its extension.The third tip is to avoid the dark areas in the picture. The sensor captures much better areas of light than shadows, so noise appears more easily in dark areas. If we avoid underexposing, the better. The noise produced by underexposure is more difficult to correct than the noise produced by raising the ISO.
It is best that you shoot in RAW if the camera allows. Being an uncompressed format, you’ll have more room to manipulate it in post production and retouch lights and shadows.There are cameras that have a noise reduction function, and also softwares like Photoshop or Premiere that have plugins with which it is possible to reduce the noise in post production, such as the denoiser effect of Premiere Color Suite and the Noise reduction in Photoshop. Although the truth is that they are not very recommendable, since this type of systems apply filters that impair in the quality of the image.
(Note: And they also require a lot of computer resources and at the time of rendering are slow and impractical processes. To give you an idea, once I applied the effect of reducing noise in a video of 50 minutes and it took me about 24 hours in Export, when normal would be about 40 minutes, depending on the power of the computer. It is best to prevent noise in the raw image).
As for the other type of noise that we have mentioned, the color noise, is caused by overheating of the sensor that normally occurs in prolonged exposures such as night photography. In this case what we have to do to avoid it is to wait between photography and photography so that the sensor does not get so hot. Or, as we have said, use the noise reduction tool that allows the camera.Well, we have given you a few tips to avoid noise, but you can also use it in aesthetic or artistic way.Do you have any other trick to avoid noise? Tell us your secrets, or anything else you want to tell us;)