Astronomik CLS CCD EOS clip filter
If you photograph deep-sky objects from a city or from locations with significant light pollution, you know how badly the orange glow above the horizon can ruin an otherwise promising night. The Astronomik CLS CCD clip filter for Canon EOS is an elegant and practical solution - simply insert it into the camera body in front of the sensor and start shooting. No screws, no adapters, no vignetting caused by large-diameter filters.
What does the CLS CCD filter do?
The CLS (City Light Suppression) filter in its CCD variant is designed to suppress emissions from sodium and mercury vapour lamps, scattered artificial light and natural airglow. This significantly darkens the image background and increases the contrast of galaxies, nebulae and star clusters against the surrounding noise.
Compared to the visual version of the filter, the CCD variant also cuts radiation above 700 nm - the infrared part of the spectrum. This means no need to combine it with a separate UV/IR blocking filter, which is required by some other filters when used with modified or natively IR-sensitive sensors.
When to choose the CLS CCD over narrowband filters
Compared to sharper narrowband filters such as UHC or OIII, the CLS CCD is a better choice for objects with a continuous spectrum - primarily galaxies and open star clusters, where a UHC filter would unnecessarily cut part of the signal. At the same time, it passes a sufficiently wide bandwidth so that exposures do not become extremely long, and the filter remains usable with slower lenses.
Clip design - the practical advantage
Astronomik clip filters are popular among astrophotographers precisely because they require no modification of lenses or adapters. The filter simply slides into the bayonet space of the Canon EOS body and holds securely in place. This is particularly convenient when you need to swap lenses quickly in the field, or when you want to use the filter with a large-aperture, fast lens where a standard screw-in filter would cause unwanted vignetting. The optical quality of the multi-layer coating ensures minimal impact on image sharpness and contrast.
Key features
- Suppresses sodium and mercury vapour lamp emissions
- Reduces airglow and scattered artificial light
- Cuts infrared radiation above 700 nm - no additional UV/IR cut filter needed
- Clip-in design for Canon EOS - no adapters or lens modifications required
- No vignetting even with large-diameter fast lenses
- Multi-layer anti-reflection coating for minimal loss of sharpness
- Ideal for galaxies and open star clusters under light-polluted skies
Who is this filter for?
The Astronomik CLS CCD clip filter for Canon EOS is an ideal starting point for anyone who wants to improve the quality of their astrophotos under light-polluted conditions, without significantly extending exposures or investing in specialised narrowband equipment. It is a reliable, everyday tool for your astrophotography kit.
