ZEISS Riflescope School

Twilight Performance Using the following formulas gives a basic evaluation of low light performance; however, one must keep in mind that they are mathematical formulas and do not take into effect some of the most critical features in optics: glass quality, number of lenses, precision of manufacturing and coatings.

Magnification Objective Lens Diameter Field-of-View Twilight Performance Exit Pupil Eye Relief Parallax Center Tube Diameter Square Reticle Adjustment Length Weight Stray Light Coatings Waterproof