Aperture device of a lens capable of close proximity flash photography

摘要

A lens includes a flash unit including a ring-shaped irradiating light source disposed around the lens barrel symmetrically about the optical axis, a diaphragm for varying the aperture diameter, an optical system having a first focusing mode in which focusing operation can be effected with respect to an object lying within a predetermined distance range and second focusing mode in which focusing operation can be effected with respect to an object lying at a distance shorter than said predetermined distance range, a control device for varying the aperture diameter in accordance with the focusing operation when said optical system is in the first focusing mode, and a device for holding the aperture diameter in the vicinity of its minimum diameter for the focusing operation when said optical system is in the second focusing mode.