The angular space observable through an optical instrument is known as what?

• A. Viewing Window
• B. Range of Vision
• C. Field of View
• D. Visual Arc

Answer: (C)

Field of view is the angular space you can observe through an optical instrument. It describes the span of the scene visible through the eyepiece or viewing optic at a given moment, typically measured in degrees or as a linear width at a specific distance. Magnification affects it: higher magnification narrows the field of view, letting you see more detail in a smaller area. There are other terms that aren’t standard in this context, such as viewing window or visual arc, and range of vision refers to what your eye can see unaided rather than what an instrument can display. So, the angular space observable through an optical instrument is known as the field of view.