The field of view is not determined from the size of the objective lens...the field of view is determined by the width of the ocular lenses. So a 7x50 binocular does not necessarily have a wider field of view than a 7x42...and may not be brighter in some cases. The field of view is measured in feet per 1000 yards. So a FOV of 350 ft. at 1000 yds. will be smaller than a FOV of 405 ft. at 1000 yds. When comparing full-sized high quality binoculars, most 10x binoculars have a smaller FOV compared to 7x binoculars. Don't be convinced by someone who claims to own a 10x binocular with a wide FOV.