Optolong CLS Filter - EOS Full Frame Clip - EOSFF-CLS

No Ratings Yet

Write a Review


  • Your Price:
  • $115.00
  • + FREE Shipping

Leave us your email, and we’ll let you know when this item is back in stock.

  • Optolong's CLS filter is perfect for observing in mild to moderate light pollution
  • Easily attaches to Canon EOS Full Frame cameras
  • Designed from Schott glass that has been multi-coated with ion-assisted deposition technology
Questions? Let our experts help!
  • Description

    Optolong CLS Clip Filter for Canon EOS Full Frame Cameras

    This CLS filter by Optolong is ideal not only for visual observations but for photo-imaging as well. This CLS filter has been optimized for Canon EOS Full Frame cameras and works great if you're viewing in an area with artificial light pollution. Due to the CLS (City Light Suppression) Filter's larger pass-band, many amateur astronomers prefer the CLS filter when observing in mild to moderate light pollution. The CLS filter selectively blocks transmission of wavelengths known for light pollution, especially artificial light pollution from high and low-pressure sodium vapor and mercury vapor lights. Using a CLS filter will even help reduce skyglow caused by naturally occurring neutral oxygen emissions in our atmosphere.

    The Optolong EOS Full Frame Clip CLS Filter is made Schott glass that has been multi-coated with ion-assisted deposition technology to ensure scratch resistance and stability on the central wavelength, or CWL. The filter cell is made of lightweight, strong metal and is CNC machined, sand-blasted, black anodized, and then laser engraved.


    Transmission Characteristics of CLS Filter

    • 95% transmission H-Beta 486nm
    • 95% transmission OIII 496nm and 500nm
    • 95% transmission H-Alpha 656nm
    • 95% transmission SII 672nm
    • 0.1% transmission Hg at 435nm and 578nm
    • 0.1% transmission Na at 589nm


    Quality Filter Materials:

    • Schott B260 substrate material from Germany, 1.0mm thick
    • CNC machined and black anodized aero-metal filter cell that is ultra-thin to provide largest clear aperture; Laser-engraved to prevent fading
    • Multiple layers of anti-reflection non-cementing coatings applied via electron-beam gun evaporation with Ion-assisted deposition


    Optolong Filter Manufacturing Processes and Parameters

    • Filter substrate is fine-optically polished to 1/4 wave and <30 parallelism over both surfaces
    • Surface quality, according to MIL-O-13830, is 60/40
    • Main nebula emission lines has a transmission of 95%
    • Off-band (major emission lines of artificial light pollution) transmission is 0.1%
    • High-value transmission of pass-band and optical density of off-band is assured through Optolong’s planetary rotation system, a homogeneous and precise coating procedure
    • Each filter comes with a plastic case with high-pressure EVA case lining


    About Optolong

    Optolong is the Astronomy Filters division of Yulong Optics, an optical filter design, and processing company out of Kunming, China that has provided filters for over 700 optical companies since 1999. All Optolong filters pass European Union RoHS requirements and have been certified by TUV Rheinland and Bureau Veritas.


    Supplier SKU


    What's Included

    • Optolong CLS Filter in Canon EOS Full Frame Clip Format

    • Filter Case

  • Dimensions & Specifications

    • Filter Size: EOS Full Frame Clip

    • Filter Type: Light Pollution
    • Filter Shape: EOS Clip
    • Mounted or Unmounted: Mounted

  • Product Guarantee

    We stand behind all the products we sell, and your satisfaction is our top priority. If you're not satisfied with the quality of your purchase, simply send the item back to us in its original packaging within 30 days of its delivery.

    Manufacturer Warranty

    Two Years

    Return & Exchange Policy

    At our site, returns are easy! You may return new, unused, and resalable items for a refund or exchange. Simply ensure that the item is returned in its original product packaging within 30 days of delivery.

  • Stars


    5 Stars
    4 Stars
    3 Stars
    2 Stars
    1 Stars

    Most Helpful Reviews

    Most Critical Reviews

    All Reviews

    Displaying Reviews 1-10 of