Optolong Filters Clip Filter for Canon EOS FF CLS (59450)

The CLS (City Light Suppression) broadband filter is designed to enhance the visibility of deep sky objects by reducing the transmission of wavelengths commonly associated with light pollution. It is particularly effective at blocking light from artificial sources such as mercury and sodium vapor lamps, as well as minimizing the unwanted 'sky glow' effect. The filter remains highly transparent to the main emission lines of nebulae, including OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha (656nm), and SII (672nm). This results in improved contrast and detail for both visual and photographic astronomy, especially in areas with moderate to high light pollution.

This version is specifically designed as a clip-in filter for Canon EOS cameras with full-frame sensors. It is compatible only with the EOS 6D, EOS 5D, EOS 5D II, and EOS 5D III. The filter is not suitable for newer models such as the EOS 6D II or EOS 5D IV, as it interferes with the movement of the flip mirror and can cause camera malfunction.

The CLS filter has a wider pass band than a UHC filter, making it suitable for use under modest to moderate light pollution. While it does not completely eliminate the effects of light pollution or increase the brightness of astronomical objects, it significantly increases the contrast between nebulae and the night sky without artificially brightening the nebula.

Important: This filter must never be used as the only solar filter.

Specifications

• Optical coating: Multiple layers

• Transmission: 80%

• Surface accuracy: 1/4

• Frame type: Clip-filter, designed for Canon EOS full-frame cameras

• Material: Schott glass

• Filter type: Broadband

• Suitable for photography: Yes

• Suitable for visual observation: Yes

This filter is a practical tool for astrophotographers and observers who want to enhance deep sky imaging and viewing in light-polluted environments using compatible Canon EOS cameras.