What is ISO?
ISO is one of the parameters of the exposure triangle of the camera. The term ISO comes from the Greek word ISO"S, which means equal. ISO again defines the International Organization for Standardization whose job is to make a standard set of international issues or products.Now the question may arise in your simple mind that what is the relationship between the ISO of the camera and an organization? Trust Me Bro has no relation. That is, although the full form of camera ISO is International Organization for Standardization, camera ISO basically means Image Sensitivity.ISO is primarily used to determine how sensitive the image will be after a certain amount of light hits the camera's image sensor. We have known in the previous blog that how the light entering the camera is physically controlled by aperture and shutter speed.But the difference in ISO is that with ISO, the light entering the camera is digitized.
How does ISO work?
The light first reflects and crosses the aperture and shutter and then hits the image sensor. Then the sensor captures it and registers it in the memory. But if it is not properly controlled after the light hits the sensor, it will be seen that the frame will be underexposed due to less light hitting the sensor, and if more light hits the sensor, it may be overexposed.To avoid such problems, the camera has a digital mechanism called ISO. ISO digitally controls the sensitivity of light hitting the camera sensor. In simple Bengali, ISO is a numerical scale that can be used to control the sensitivity of the light entering the camera.
What is the ISO range?
Naturally, the lower your ISO value, the less sensitive your image sensor will be and the darker your image will be. Again, as you increase your ISO value, the more sensitive the image sensor will be, the brighter your image will be.So you can get properly exposed images by increasing the ISO when you shoot in low light and lower the ISO when you shoot in high light, right?
Why does noise come when ISO is increased?
If you reduce the ISO and expose the frame, it's okay, there is no problem. But the problem is when you increase the ISO and go to overexpose the frame. There is a saying in Bengali that to get something you have to give something. Similarly, when you want to take higher ISO, digital noise should be introduced to the sensor in return.Normally increasing the ISO will produce a kind of digital noise in the image as a result of the Sensor Sensitivity Amplified. That looks bad. Although there are creative uses of digital noise, if you want to know about them, you can comment below, we will discuss them in the next blog.However, the only solution to this noise problem is to shoot at Base ISO.
What is Base/Native ISO?
The minimum ISO value given by your camera is basically called Base ISO or Native ISO. Although there are exceptions in some cases, such as Arri Alexa Mini's minimum ISO Range is 160, but its Base/Native ISO is 800.
Shooting at native ISO offers 2 advantages:
1/ Digitalk can reduce noise.
2/ Wide dynamic range is available.
Dynamic range measures the limits of how dark and bright an image can be without losing image details.As shooting at Base/Native ISO gives large dynamic range which results in much higher image details and color ranges which is a definite plus point for filmmakers. So to get a proper image we should try to shoot in Base/Native ISO.Since low light situations require more light, it is better to use artificial light instead of increasing the ISO. Still, if there is no Enough Light system, then you can increase the ISO a little and adjust the exposure. But make sure that noise does not come as a result of high ISO setting.
Conclusion of ISO
So that was all the basic ISO elements of filmmaking. If you are interested in filmmaking and have trouble understanding something, you can comment. Thanks for taking the time to read the entire blog.
