Free lens aperture diaphragm illuminating method and illuminating system

The invention relates to a free lens aperture diaphragm illuminating method and an illuminating system. The method comprises the following steps of (1) arranging an LED (Light-emitting Diode) array light source, wherein the LED array light source is formed by combining a plurality of LED light sources and is provided with a light source principal axis; (2) arranging a variable field diaphragm on the light source principal axis; (3) arranging a control unit, wherein the control unit is respectively connected with the LED array light source and the variable field diaphragm; (4) according to the required lens aperture diaphragm energy distribution demand and an exposure field range, controlling the corresponding LED light source emergent light power and the light blocking range of the variable field diaphragm through the control unit, and completing corresponding free lens aperture diaphragm illuminating. According to the free aperture diaphragm illuminating method and the illuminating system provided by the inv