The Optolong L-Pro clip-in filter reduces the effect of artificial light pollution and natural skyglow for visual observing and for photographic applications with color CCD and DSLR cameras. While the Optolong UHC and CLS filters help to block the effects of light pollution, they pass light only in the green and red part of the visible spectrum. The L-Pro filter has a more sophisticated multi-layer coating that not only passes green and red light, but also blue and yellow/orange light. This results in a more natural color cast in images of deep-sky objects. The filter also suppresses IR wavelengths for photographic applications.

The Optolong L-Pro clip-in filter improves image contrast by passing light from many types of nebulae while selectively blocking the transmission of light from high and low pressure sodium vapor and mercury vapor lights as well as skyglow caused by naturally occurring neutral oxygen atoms in Earth’s atmosphere. The filter passes light emitted by hydrogen atoms (at 486nm and 656nm), oxygen ions (at 496nm and 500nm), nitrogen ions (at 654nm and 658 nm), and sulfur ions (at 672nm). These bands of light are emitted by emission nebulae such as the Orion and Lagoon Nebulae, planetary nebulae such as the Ring and Cat’s Eye Nebulae, and by supernova remnants such as the Veil Nebula. The filter can also help improve the contrast of stars and galaxies against the background sky, especially in photographic applications. The filter can also help improve the contrast of stars and galaxies against the background sky without sacrificing color balance, especially in photographic applications.

Compatibility List:

This filter will/will not work with the following camera models:

• Canon EOS 6D Yes
• Canon EOS 5D Yes
• Canon EOS 5D MkIII Yes
• Canon EOS 5D MkII Yes
• Canon EOS 6D II No
• Canon EOS 5D IV No