How much of a lens can be obscured and still effectively photograph a subject under surveillance?

When considering how much of a lens can be obscured while still effectively photographing a subject, it's important to understand the mechanics of light transmission and image capture. A lens functions by gathering and focusing light onto a sensor or film. If a significant portion of the lens is obscured—up to 85-90%—the remaining portion can still gather enough light to produce a recognizable image.

In this case, the lens can still receive sufficient light through the unobscured part, thereby allowing the camera to still operate effectively. This ability to capture images despite substantial obstruction can be particularly relevant in surveillance photography, where angles and direct lines of sight may be limited due to the environment or specific operational concerns.

When a lens is obscured by 85-90%, the small percentage of the lens that remains clear can still function adequately. This is a critical aspect of understanding how cameras may be utilized in challenging conditions or covert scenarios. Conversely, higher levels of obscuration would drastically decrease the overall quality and clarity of the captured image, which explains why higher percentages are more viable for effective photography.