Humminbird Wide 3D Vision - Manual (Page 27)

ZOOM
Another form of range control is Zoom. Zoom allows
selection of various ranges for full screen viewing.,
while maintaining a view of the full range. By using
the display to view a smaller area, the effective
display resolution is increased, and the unit’s ability to
separate targets close together is enhanced.
The zoom range is determined by the depth range in
use when Zoom is enabled. In shallow water, when
the 15 foot or 30 foot depth range is used, the zoom
range will be 7 ½ feet. If the 60 foot or 120 foot depth
range is in use, the zoom range will be 15 feet. And if
the 180 foot or 240 foot depth range is in use the
zoom range will be 30 feet. For depths greater than 240 feet the display will only update a 2D
view. If the depth range is 480 feet the zoom range will be 30 feet and if the depth range is 600
feet or 1000 feet the zoom range will be 60 feet.