An achromatic lens, also referred to as an achromat, typically consists of two optical components cemented together, usually a positive low-index (crown) element and a negative high-index (flint) element. In comparison to a singlet lens, or singlet for short, which only consists of a single piece of glass, the additional design freedom provided by using a doublet design allows for further optimization of performance. Therefore, an achromatic lens will have noticeable advantages over a comparable diameter and focal length singlet.

 

An achromatic lens is far superior to a simple lens for multi-color "white light" imaging. The two elements composing an achromatic lens (literally, "a lens with no color") are paired together for their ability to correct the color separation inherent in glass. Having eliminated the problematic chromatic aberrations, an achromatic lens becomes the most cost-efficient means for good polychromatic illumination and imaging.

 

 

The filter can remove the reflections from the non-metallic surfaces like water and glass.

With this filter, color saturation can be improved significantly especially outdoors and landscape.

It enhance contrast and the colors shall become brighter and cleaner in the photo.

Double Thread which can install the screw mount lens hood.