Principle of the Center Dual Cross-Hair Sensors: In an AF sensor, because there is the correlation between the subject contrast detected using lines and the distance metering, the alignment of the line sensor can be affected by the direction of any lines in the image. (For instance, a vertically positioned line sensor has weakened focusing on a vertically striped image.) To overcome this problem, '+ shape' sensors were developed in which horizontal and vertical line sensors overlap to form a cross. However, in the Dynax 7, this has been taken one step further by superimposing 'x shape' sensors on the '+ shape' sensors to create the world's first center dual cross-hair sensors. First, the subject image passing through the lens is divided and resolved by sensors in eight locations within the secondary imaging lens. An image divided by vertical and horizontal lines (into four segments) is resolved by the '+ shape' sensors for maximum apertures of f/6.7 or faster, whereas an image divided diagonally (also into four segments) is resolved by the 'x shape' sensors for maximum apertures of f/2.8 or faster. The resulting data of the 8-segments are then analyzed to obtainextremely precise focusing data.