Interferometric Laser Imaging Technique (ILIT) is applied to nuclei size measurements in cavitation tunnel. The use of a large collection angle optics is needed to allow nuclei size measurement down to 10 µm at 1 m distance. The negative effect of spherical aberration in such a situation is exhibited. A lens assembly, free from spherical aberrations and specifically designed for this application is presented. Measurements in a cavitation tunnel shows nuclei size distributions in the range 10-200µm. In addition to bubble sizes, ILIT can provide information on bubble concentration. To do so, a measurement volume is defined from statistical information extracted from the ILIT results themselves.