An ellipsometer apparatus (100, 200, 300, 350, 400) for performing metrology of a semiconductor sample, comprising: an illumination optics module (102, 302, 402, 702) for providing an illumination beam at a plurality of wavelengths and directing the illumination beam towards the sample at a plurality of angles of incidence AOI's and/or azimuth angles AZ's; a collection optics module comprising a detector module (124, 224), the collection optics module configured to collect an output beam emanating from the sample at a plurality of discrete ranges of AOI and/or AZ and further configured to direct the output beam to the detector module (124, 224), the collection optics module further comprising apertures configured to collect each discrete range, centered on a different AOI and/or AZ, one at a time, and the output beam being in response to the illumination beam on the sample, wherein the illumination optics module (102, 302, 402, 702) includes polarization generating optical elements for generating a plurality of polarization states for the illumination beam, the collection optics module includes polarization analyzing optical elements for analyzing the polarization state of the output beam, wherein the illumination optics module (102, 302, 402, 702) and collection optics module include reflective optical elements between the polarization generation optical elements and the polarization analyzing optical elements; the detector module (124, 224) for receiving and detecting the output beam from the sample at the discrete ranges of AOI and/or AZ and the polarization states and generating a plurality of signals based on the output beam at the discrete ranges of AOI and/or AZ and the polarization states; one or more controllers (230, 330, 430) that are each configured to control one or more of the following: selecting a wavelength range, selecting one or more of the discrete ranges of AOI and/or AZ for collection of the output beam, selecting the polarization states, and analyzing the signals at the discrete ranges of AOI and/or AZ and the polarization states to determine a characteristic of the sample; characterized in that the wavelengths are selectable within a range from a vacuum ultraviolet VUV to an infrared IR wavelength, wherein the range of wavelengths is between about 150 nm to about 2000 nm; and in that the illumination optics module (102, 302, 402, 702) further comprises one or more beam shaping optical elements for shaping the illumination beam and controlling the point spread function of a focus at a target on the sample for each of the discrete ranges of AOI and/or AZ; wherein the one or more beam shaping elements comprise a plurality of apodizers, which each possess an optical function that cannot be reconfigured, and the apparatus (100, 200, 300, 350, 400) further comprises a positioning mechanism for moving selected ones of the apodizers into or near a plane that is conjugate to a pupil of the illumination beam, wherein the apodizers provide predefined illumination profiles corresponding to all of the discrete ranges of AOI and/or AZ, and wherein the controller is further configured for causing the positioning mechanism to move a selected one of the apodizers. an illumination optics module (102, 302, 402, 702) for providing an illumination beam at a plurality of wavelengths and directing the illumination beam towards the sample at a plurality of angles of incidence AOI's and/or azimuth angles AZ's; a collection optics module comprising a detector module (124, 224), the collection optics module configured to collect an output beam emanating from the sample at a plurality of discrete ranges of AOI and/or AZ and further configured to direct the output beam to the detector module (124, 224), the collection optics module further comprising apertures configured to collect each discrete range, centered on a different AOI and/or AZ, one at a time, and the output beam being in response to the illumination beam on the sample, wherein the illumination optics module (102, 302, 402, 702) includes polarization generating optical elements for generating a plurality of polarization states for the illumination beam, the collection optics module includes polarization analyzing optical elements for analyzing the polarization state of the output beam, wherein the illumination optics module (102, 302, 402, 702) and collection optics module include reflective optical elements between the polarization generation optical elements and the polarization analyzing optical elements; the detector module (124, 224) for receiving and detecting the output beam from the sample at the discrete ranges of AOI and/or AZ and the polarization states and generating a plurality of signals based on the output beam at the discrete ranges of AOI and/or AZ and the polarization states; one or more controllers (230, 330, 430) that are each configured to control one or more of the following: selecting a wavelength range, selecting one or more of the discrete ranges of AOI and/or AZ for collection of the output beam, selecting the polarization states, and analyzing the signals at the discrete ranges of AOI and/or AZ and the polarization states to determine a characteristic of the sample; characterized in that