Personally, even for low-key nighttime scenes, I prefer not to crush my blacks on initial recording. Use light, as much of it as you can afford. A exterior nighttime scene in a Hollywood movie could easily have 18K HMIs on scaffolding running.
I'ts about shaping and controlling the ratio of light. Get enough light in the scene, and you can use a low ISO, and still stop down. But really, even then, don't presume to make the picture as dark as you want it in the final film in camera. If you can, shoot brighter, since you won't clip the highlights here - and then crush your blacks to taste in post.
I frequently have Directors and Producers look at field monitors and tell me to close the iris down and make the picture darker. But if I indulge them, there won't be as much information to manipulate in post.
Very cool trick. I did not know that, so thank you VERY much for teaching me!!
Best Regards Viddovation :happy: