A simple question with tough answers. "Dark" is defined differently by each of us. You will always need light to create an image. Many security pros use infrared illumination to provide "invisible" light on a scene that certain cameras can use to help produce a usable image. Without IR the task becomes much more challenging.
Starlight is a new technology that allows for images to be produced by the security camera in ultra-low-light situations. Below is a short video about what a camera with Starlight can see versus a camera without.
Learn more about Starlight, now available in a fixed mini dome or a pan-tilt-zoom camera.