05 Jan 2022 Ecoptik (also known as BRD Optical) provides meniscus lens in both positive and negative focal lengths. These lenses are useful when used with another lenses to increase or decrease the focal length. This lens element configuration does not introduce any additional coma or spherical aberrations.
Ecoptik (also known as BRD Optical) provides meniscus lens in both positive and negative focal lengths. On the aspect of shape, it can be divided into convex and concave meniscus lens. On the aspect of the effect, it can be divided into diverging and converging meniscus lens. | 
