Rendered images can be saved as IFF files. These IFF files have RGBA data with no depth map, by default. For example:
Light sources in Maya can read and write shadow maps. These shadow maps are stored as a depth map in an IFF file. The depth map may be either a traditional Z buffer or a midmap. The stored value for a midmap is half of the distance between the first and second surfaces. Midmaps reduce the number of incorrect self shadowing occurrences.
Different light sources produce different shadow maps. A spot light subtending an angle below 90 degrees will produce one shadow map. If the subtended angle is greater than 90 degrees, it will produce five shadow maps - one central and five peripheral. A point light will produce one shadow map in a simple scene, and up to six shadow maps in more complicated scenes.