In this article, I’m going to talk about the dual ISO capability of the Blackmagic Pocket Cinema Camera 4K (BMPCC 4K) along with the new Blackmagic RAW (BRAW) to get better-exposed video footage. While there is a lot of technical information we could talk about, I thought I’d jump straight to how we can use this technology.
The BMPCC 4K has what is called dual ISO. What that means is that there are two separate ranges that we can use on the camera depending upon how bright or dark the subject we are recording. In some ways, it’s almost like having two different cameras because when we switch from one range of ISO to the other, the camera’s light handling capabilities change. In the chart below (from the BMPCC 4K User Manual), Range 1 is from ISO 100-1000 (see the red rectangle) and Range 2 is from ISO 1250-6400 (see the blue rectangle).
An important aspect of ISO is how it impacts the dynamic range of the camera. You can think of the dynamic range as to how well the camera maintains information or detail based upon what the ISO set to. Looking at the chart above, the yellow areas are the number of stops of brightness/highlights (stops above middle gray or middle brightness in the scene), while the orange areas are the number of stops of darkness/shadows supported by that ISO. The bigger the number, the brighter or darker the scene can be and still show detail in those areas.
For example, take a look at ISO 1000. You will see that is it has 6.8 stops (yellow area) above the middle compared to ISO 100 which has 3.5 stops. What this tells us is that ISO 1000 will allow for more detail with a brighter subject like clouds in the sky on a sunny day or a bright day at the beach or on set with a very brightly lit scene. On the other hand, let’s say I’m shooting a scene that is very dark and I need the maximum number of stops below the middle point. In looking at the chart above we see that I need to move to Range 2 and ISO 1250 gives me 8.5 stops below middle gray and the maximum amount of detail in my darkest area of the scene, but only 3.8 stops above the middle for the bright areas.
Picking the correct range is important. With BRAW and DaVinci Resolve, we can move around within either Range 1 or Range 2 after the fact. I can change the ISO in the editor, but I’m limited to doing that within each Range.
So generally I’d suggest using Range 1 for brighter lit or brighter daylight scenes and Range 2 for darker scenes or dusk or night time scenes. Another thing to consider is that the higher the ISO, the more noise that is introduced into the recording, so always evaluate the scene carefully and choose the best combination of dynamic range (stops above and below the middle) and noise level. The other area to look at is how changing the ISO affects the color. This is an area you will have to explore on your own. Some people feel that the color looks better at the native ISO (400 in Range 1 and 3200 in Range 2), but this is something that you’ll need to try on your own.
So what about ISO 8000 and above? I typically don’t shoot at those ISO because of the additional noise. It’s nice to know that they are available, but I will always try to shoot within Range 1 or Range 2.
So that’s a quick look at the dual ISO’s with BRAW on the BMPCC 4k. Thanks for reading and I hope you found the article helpful.