Optical Performance - Optional eyepiece module required: straight (STX) or angled (ATX) viewing and binocular viewer (BTX) available - Large 85mm objective lens draws in more light than the smaller module and produces a larger exit pupil for improved low-light performance - Extra-low dispersion fluoride HD glass limits chromatic aberrations to produce clearer and sharper views with little or no color fringing - Field-flattener lens system eliminates spherical aberrations to eliminate distortion at the edges of the field of view - Anti-reflection SWAROTOP lens coatings reduce glare and improve contrast, color rendition, and clarity - Scratch-resistant SWARODUR coatings protect exterior lens surfaces
