Field of view comes into play when purchasing binoculars. It indicates how wide you can see at 1000 yards. If the field of view is wide you can see the whole back field in motion but the detail may be fuzzy. Generally with lower magnification, you get a wider field of view but the edges can distort.
Infinity focus is possible with all binoculars...the "men from the boys" binoculars are separated by close focus. For avid birders 10 feet or less is desirable in a close focus. If you are particularly interested in this aspect of binoculars, you can get down to a nifty three feet.