Three-dimensional microscopy suffers from sample-induced aberrations that reduce the resolution and lead to misinterpretations of the object distribution. In this paper, the resolution of a three-dimensional fluorescent microscope is significantly improved by introducing an amplitude diversity in the form of a binary amplitude mask positioned in several different orientations within the pupil, followed by computer processing of the diversity images. The method has proved to be fast, easy to implement, and cost-effective in high-resolution imaging of casper fli:GFP zebrafish. © 2018 Optical Society of America.