Select this option to enable elliptical filtering for the selected file texture.

Sets the maximum size (in texture pixels) of the minor radius of the ellipse at the largest pyramidal level. Use this slider to tweak your filtering. Increasing the anti-aliasing level gives better filtering but increases lookup time and therefore decreases the rendering speed.

The Convert File to Optimized Format attribute is the override for the global Use optimized textures (auto-conversion) option in the Preferences window, under the Rendering section. The global option converts all textures in your scene to the optimized format while this option within the file node only converts the selected texture to an optimized format. To override the global setting, select the Override Global Auto-Conversion Settings attribute and then use Convert File to Optimized Format to choose whether or not to convert your file to an optimized format. See Mental Ray Preferences in the Basics guide for more information.