To achieve the sharpest possible image with Night Mode's extended exposure times, what is the single most critical practical requirement for the iPhone during capture?

The single most critical practical requirement for the iPhone during capture to achieve the sharpest possible image with Night Mode's extended exposure times is absolute stillness of the device. Night Mode utilizes extended exposure times, which means the iPhone's camera sensor gathers light over a longer duration, often ranging from one to several seconds, depending on the available light. During this prolonged period of light collection, any movement, however slight, of the iPhone itself will cause the light from a single point in the scene to register on multiple pixels across the sensor's surface. This phenomenon is known as motion blur, and it results in an image that appears soft, streaky, or unfocused rather than sharp. To prevent motion blur and ensure optimal sharpness, the iPhone must be held perfectly steady without any vibrations or shifts throughout the entire extended exposure duration. This typically necessitates placing the iPhone on a completely stable surface or mounting it on a tripod, allowing each individual light point to be precisely captured on its intended pixel without displacement.