Enhanced Definition Lens Tube. Website. A lens tube for the ETC Source Four ERS that offers sharper imaging and higher intensity (about 10% greater). Available as an option for 19°, 26°, 36°, and 50°; and standard on the 14°, 70°, and 90°. Not available for the 5° and 10°. Unlike the others (except 36°), all EDLTs have two lenses.
