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ZWO EOS Lens Adapter for EFW

ZWO EOS Lens Adapter for EFW

by ZWO
SKU ZWO-EFW-EOS-II
$49.00 USD - $49.00 USD
$49.00 USD
$49.00 USD - $49.00 USD
$49.00 USD
Price Match Policy!
  • Connects Canon EF lenses to ZWO Electronic Filter Wheels (EFW); EF-S lenses are not supported
  • Engineered for ZWO cameras with 6.5mm back focus (e.g., ASI1600)
  • Adds 17.5mm of spacing to complete the 44mm Canon EF flange distance (6.5mm + 20mm EFW + 17.5mm)
  • New fixed design: this version is not adjustable
2 in stock
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • ZWO EFW-EOS Lens Adapter for 6.5mm Back Focus Cameras

    The ZWO EFW-EOS Adapter is the essential mechanical link for attaching Canon EF lenses to a ZWO Electronic Filter Wheel (EFW) and a cooled camera with 6.5mm of back focus. This new, non-adjustable adapter adds the 17.5mm of spacing needed to reach the 44mm Canon EF flange distance, enabling you to use your high-quality camera lenses for wide-field astrophotography with filters.

    Canon Lens Integration for 6.5mm ZWO Cameras

    This adapter solves the specific back focus challenge of using Canon EF lenses with ZWO's popular 6.5mm back focus cameras, like the ASI1600 series, and an EFW. By bridging the mechanical and spacing gap, it enables wide-field imaging with proven telephoto optics, correctly establishing the 17.5mm distance required for a sharp, flat field with a filter wheel in the optical train.

    Fixed, Non-Adjustable Design

    This newer version of the ZWO EFW-EOS adapter is unadjustable: its 17.5mm extend distance is fixed, so the spacing between your lens and filter wheel is set by design.

    ASI1600 & EFW Wide-Field Imaging

    The primary use for this adapter is pairing a workhorse camera like the ZWO ASI1600 with a 7 or 8-position EFW and your existing Canon lenses. This combination turns your camera lens into a powerful, compact astrograph for capturing large targets like the Andromeda Galaxy (M31) or the Rho Ophiuchi cloud complex without requiring a telescope.

  • What is the purpose of the ZWO EFW-EOS adapter?

    This adapter allows you to connect a Canon EF lens (EF-S lenses are not supported) to a ZWO Electronic Filter Wheel (EFW), which is then connected to a ZWO camera with 6.5mm of back focus. Its 17.5mm length, added to the camera's 6.5mm and the EFW's 20mm, gives the 44mm Canon EF flange distance needed for sharp focus across the entire sensor.

    How do I use this adapter to image the North American Nebula (NGC 7000) with my Canon lens and ASI1600?

    Attach your Canon lens to this adapter, thread the adapter onto the front of your ZWO EFW, and then connect your ZWO ASI1600 camera to the back of the EFW. This creates a rigid, wide-field imaging rig perfect for large emission nebulae like NGC 7000, allowing you to use narrowband or LRGB filters with your camera lens.

    Will the ZWO EFW-EOS adapter work with a full-frame camera like the ASI6200MC Pro?

    No, this adapter is specifically designed for ZWO cameras with a 6.5mm back focus. Cameras like the ASI6200MC Pro have a different native back focus (17.5mm) and require a different adapter solution for use with Canon lenses and a filter wheel.

    Can I control the aperture of my Canon EF lens with this adapter?

    No, the ZWO EFW-EOS adapter provides a purely mechanical connection. It does not transmit electronic signals for aperture or autofocus control. Aperture must be set on the lens itself, if the lens has a manual aperture ring.

    Do I need this adapter to connect my Canon lens directly to a ZWO camera without a filter wheel?

    No, this adapter is specifically for integrating a ZWO Electronic Filter Wheel (EFW) into the imaging train. For a direct camera-to-lens connection, you would need a different ZWO EOS-T2 adapter designed for that purpose.

  • SKU Number ZWO-EFW-EOS-II
    Lens Mount Canon EF (EF-S not supported)
    Camera Side Connection ZWO EFW (Electronic Filter Wheel)
    Required Camera Back Focus 6.5 mm
    Adapter Optical Length 17.5 mm
    Product Type Filter Wheel Adapter
    Telescope-Side Connection Canon EF female

    • Short EOS Adapter for EFW (Gen II)

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  • ZWO 2-Year Limited Warranty