In this video you will learn about the dual ISO technology featuring the Black Magic Pocket Cinema Camera 4K. You will also understand why using the lowest ISO can sometimes degrade your recorded image.
Once again John Hess from Filmmaker IQ gives an informative and in-depth presentation on how ISO works in our cameras and what this modern dual ISO technology is. The information is applicable not only to cinema cameras, such as the BlackMagic Pocket Cinema Camera 4K, but also to other cameras that feature the dual ISO function. Do not get discouraged if your camera doesn't support it, because the details you will learn about not always using the lowest ISO is applicable to any digital camera on the market.
The dynamic range of the camera highly depends on the voltage gain you apply to the sensor, or the ISO setting. It is technically challenging to keep the same dynamic range throughout all the ISO values the camera allows. This is why certain manufacturers decided to split the range of ISO values in two parts that give you a different dynamic range. Think of the dynamic range as the ability of the camera to preserve detail in the shadows and in the highlights. Some ISO values will give you more detail in the shadows, while others, in the highlights. It is good to get familiar with the ISO and dynamic range charts for your camera and see at what values your dynamic range will be the greatest for the lighting situation you have. Below is the chart for the BMPCC4K camera.
You can clearly see the two ranges the manufacturer split the ISO values into. For example, if you are at a scene and you have lots of highlights and less shadows, you better shoot at ISO 1000 on that camera because it will give you more information in the brightest parts of the image. This is quite counter-intuitive to what we have been taught so far. The same peculiarity applies for all other cameras which may or may not support dual ISO. Here's the same chart but for the Canon C100 cinema camera.
For those who want to understand more about that phenomena, watch the following video that describes dynamic range and ISO in a greater detail.
We hope the information given by the Filmmaker IQ YouTube channel was helpful. Feel free to post the dynamic range chart for your camera in the comments below.