There seems to be no limit to the minutiae that can be displayed in a camera’s viewfinder. Focal distance, zoom percentage, date and time, battery condition, shutter, and umpteen other things, all contribute to the clutter; indeed, there is no shortage of miscellany that can obscure the viewing image and the edges of the frame
Many camcorders now offer a customizable VF display that gives us new reason for life. I prefer a clean view with only the essential functions: timecode, battery level, record time, focus, iris, zoom, frame rate, and audio level. The frame outline or action safe is also crucial of course to ensure accurate composition and sufficient headroom.
Not so safe
The action safe specifies a ten percent cut-in from each side of the frame; the title safe indicates twenty percent. The notion of title and action safe zones assumes that a portion of the transmitted image will be cut off in the home television. Modern viewing environments including laptop computers with thin frames seldom intrude more than a few percent into picture so the traditional 20% title safe seems like overkill many times over.
For me the rangefinder is also a vital part of my viewfinder complement as the numerical readout in feet or meters greatly facilitates the setting of non-critical focus when shooting in documentary or run-and-gun environments.
The zoom readout is less critical although shooters of narrative-type programs will often note this setting to match frame size in a reaction shot or to ensure continuity in case of a reshoot. The zoom setting may be expressed in millimeters or percentage.