The iPhone can capture great video when lighting is less than ideal, but as the environment gets darker, the quality will begin to suffer even with Apple's latest model. Dimmer videos with duller colors and noise in the shadows are rarely what's wanted. The good news is that there are several things that can be done to help improve indoor and nighttime video recording.
Apple uses Night Mode, HDR, and DeepFusion to improve photography and capture incredible detail and realistic color even in very dark conditions. Since video recording needs to capture several photos every second, it presents a more demanding challenge. This also means that there is less time to use computational photography tricks to brighten and improve the image. With video, the iPhone must move on to the next image in a split second.
One way to adjust the iPhone camera to improve low-light video recording is to lower the frame rate, which means capturing fewer still images each second. By allowing the camera additional time between frames, it can let in more light before moving to the next image. While the iPhone 13 can record 4K resolution at 60 frames-per-second, lowering the frame rate by tapping the upper-right corner and changing to 30 or 24 will capture brighter videos with less noise when lighting is dim. Apple has an Auto-FPS option under the camera section in the Settings app that allows the iPhone 12 and 13 to automatically make this switch.
Best Low-Light iPhone Camera
Over the last several years, the iPhone has featured more than one rear camera. The main camera always has the best specifications, including a wider aperture. Using the main camera which appears as '1x' in the camera app will capture the most light. If an ultra-wide (0.5x) option is available, it is second best and telephoto, which might appear as '2x,' 2.5x,' or '3x,' will be the darkest camera.
Of course, the LED light on the iPhone can also be enabled by tapping the icon. This will provide good lighting within a few feet of the phone but won't help at a distance. Using the LED might ruin the ambiance and so it usually isn't the best way to record video, although this does depend on the subject. By lowering the frame rate and choosing the camera with the largest aperture, it's possible to capture brighter videos with an iPhone in poor lighting, while picking up more color, and reducing noise.
Source: Apple