The invention relates to an optical imaging device, in particular an objective 1 for microlithography in the field of EUVL for producing semiconductor components, having a beam path 2, a plurality of optical elements 3 and a diaphragm device 7 with an adjustable diaphragm opening shape. The diaphragm device has a diaphragm store 7a, 7b with a plurality of different diaphragm openings 6 with fixed shapes in each case, which can be introduced into the beam path 2.