Wait, I vaguely recall reading about a binocular I think that that might include a camera, is that what you mean?
I believe that 'Monocular' and 'Binocular' are terms used for viewing by eye. Not sure what you are after. Monocular? For viewing by eye often magnifications are given, 7X binoculars, or 10X Monocular, etc. The "X" usually means it is that much bigger than when viewed by eye. A person would be 7X taller, etc.
Do you mean a camera with a telephoto lens
for a video camera? Or to find a telephoto lens for a camera that you already have.
For cameras, long focal length lenses are usually specified as "35 mm equivalents" -- the approximate horizontal and vertical fields of view of the old 35 mm film
cameras in use for so many years. This is too complicated to explain in a forum. I'd suggest that you search "35 mm equivalent" . Then when you get the spec for a video camera lens you will be able to get an idea of the field of view covered. Using 35 mm equivalent specifications is a very poor system so don't feel bad if it is not clear. Using the '35 mm equivalent' specs Telephoto lenses will be listed as having focal lengths such as 200 or 300mm and greater.
This camera lists an especially long focal length of 600mm BUT I believe that it is an electronic feature and not of the lens itself.
Look at the lens specs that show the focal length range of the zoom lens. Search to see what angle is covered by horizontal and vertical fields of view.
Find Youtube instructional videos like this - Search: 35 mm equivalent Youtube