Binoculars and monoculars with low-dispersion ED glass

 

— the presence in the design of the optical device of lenses made of low-dispersion glass: ED (Extra-low Dispersion), LD (Low Dispersion), SLD (Special-low Dispersion), ELD (Extraordinary-low Dispersion), UL (Ultra-low Dispersion), etc.

Such elements in the optical design are responsible for minimizing the level of dispersion – this phenomenon is characterized by the “stratification” of the light stream after refraction, since different parts of the spectrum are refracted at different angles. Dispersion entails a loss of image clarity and provokes the appearance of chromatic aberrations – coloured borders at the boundaries of high-contrast transitions along the edges of individual objects. Low dispersion glass ensures refraction of all light waves at the same angle, thereby minimizing chromatic distortion and improving colour reproduction and resolution parameters. At the same time, the use of such glass significantly affects the cost of the optical device, so low-dispersion glass often remains the prerogative of high-end models.