Astronomik CLS Visual Clip-Filter for Canon EOS Cameras
Astronomik CLS Clip-Filter for Canon EOS CamerasThe Astronomik CLS light pollution filter works on all objects for both visual use, and imaging with standard and Baader modded DSLR cameras. Blocks Sodium, Mercury and air-glow emission typically from street lighting. It is a great deep sky and general purpose filter. Not UV / IR blocked.
The patented Astronomik Clip-Filter System is made from black anodized aluminum and can be inserted within seconds directly into a Canon EOS camera body. There are no changes necessary and all lens functions (focus, screen, image stabilization) remain functional! Almost all Canon system lenses (with the exception of the EF-S series) and all M42 and T2 lens adapters, can be used with the Astronomik Clip-Filter System. The Clip-Filter System also acts as a very effective dust shield, which prevents the possibility of dust settling on the sensor during long exposure imaging.
Important: Not suitable are cameras offered before 2003 and all varieties of the Canon EOS 1D, EOS 5D and EOS M. Please visit the Astronomik EOS Clip Filter page for full fitment details.
The filters are optimized for use with aperture ratios from 1:3 to 1:15. Transmission losses and chromatic distortions, which are problems with other filters, only appear with Astronomik filters when extremely bright aperture ratios of 1:2 and more are used. The CLS filter is suitable for use with telescopes of all aperture sizes.
- Visual observation (dark skies): Good, to reduce light pollution by mercury-vapour lamps (streetlight)
- Visual observation (urban skies): Good, an UHC-E or UHC filter is more suitable
- Film photography: Very good, colour balance is near perfect
- CCD photography: Good, when used with an additional IR-block-filter (!)
- DSLR photography (astro modified): Very good, colour balance is near perfect
- DSLR photography (MC modified): Good, when used with an additional IR-block-filter
- DSLR photography (original): Good, colour balance shifted but contrast enhanced
- Webcam / Video (Planets): Unsuitable
- Webcam / Video (Deep Sky): Very good, if light pollution is a big problem
- 97% transmission at 656nm (H alpha)
- 92% transmission at 486nm (H-beta)
- 92% transmission at 496nm (OIII)
- 92% transmission at 501nm (OIII)
- pass from 450 to 540nm and beyond 650nm
- Parfocal with other Astronomik filters
- Glass thickness: 1mm
- Completely resistant against high humidity, scratches and aging effects
- Diffraction limited, the filter will not reduce the optical performance of your telescope!
- Astronomik filters are delivered in a high-quality, long lasting, filter box
- The horizontal axis is the Wavelength in Nanometers (nm). 400nm is deep blue, at 520nm the human eye senses green and at 600nm red. At 656nm is the famous "H-Alpha" emission line of hydrogen.
- The transmission in % is plotted on the vertical axis.
- The red line shows the transmission of the filter.
- Visual filters: The grey line in the background shows the relative sensitivity of the human eye at night. The maximum is at ~510nm and drops to longer and shorter wavelengths. You can easily see, that you can´t see anything of the H-alpha line at night (even if you can during daylight!) The sensitivity at 656nm is 0% at night!
- Photographic filters: The grey line in the background shows the sensitivity of a typical CCD sensor.
- The most important artifical emission lines are shown in orange. The artifical light pollution is dominated by see mercury (Hg) and sodium (Na), which are used in nearly all streetlights.
- The most important emission lines from nebulas are shown in green. The most important lines are from ionized Hydrogen (H-alpha and H-beta) and double ionized oyxgen (OIII).