Traditional Culture Encyclopedia - Photography major - What is a semi-isocenter point?

What is a semi-isocenter point?

The isocenter is the intersection point of the angular bisector of the angle between the main optical axis of the aerial camera and the main vertical line (that is, the ground vertical line passing through the center of the objective lens) and the image plane.

Isocenter

The isocenter is the angle bisector of the angle between the main optical axis of the aerial camera and the main vertical line (that is, the ground vertical line passing through the center of the objective lens). The intersection point of the image plane; often represented by c, for horizontal aerial photos, the isocenter coincides with the principal point of the image. The greater the tilt angle of the image, the greater the distance between the isocenter and the principal point of the image.