What is a key use of binoculars in private investigation?

The primary function of binoculars in private investigation is to observe distant subjects. Binoculars allow investigators to gain a clearer and magnified view of people, activities, or events that are far away, which is crucial for surveillance operations. This capability enables private investigators to collect evidence without being intrusive or detected, thereby maintaining a degree of anonymity while observing potentially sensitive situations.

The other options do not align with the practical applications of binoculars. Watching videos and recording audio are tasks better suited for cameras and audio devices, respectively, while computing data falls outside the physical observational capabilities offered by binoculars. Therefore, the role of binoculars as a tool for distance observation in investigative work stands out as essential for effective private investigation.