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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
ZWO EOS Lens Adapter for EFW

ZWO EOS Lens Adapter for EFW

by ZWO
SKU ZWO-EFW-EOS-II
$49.00 - $49.00
$49.00
$49.00 - $49.00
$49.00
Price Match Policy!
  • Connects Canon EOS lenses to ZWO Electronic Filter Wheels (EFW)
  • Engineered for ZWO cameras with 6.5mm back focus (e.g., ASI1600)
  • Establishes the correct 17.5mm back focus distance for the optical train
  • Second-generation design with an improved, secure locking mechanism
1 in stock
Qualifies for FREE Shipping in CONUS on orders over $350.
  • 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 EOS lenses to a ZWO Electronic Filter Wheel (EFW) and a cooled camera with 6.5mm of back focus. This second-generation adapter features an improved locking mechanism and correctly sets the total back focus to 17.5mm, 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 EOS 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.

    Generation II Locking Mechanism

    As the second-generation version, this ZWO EFW-EOS adapter has been redesigned with a more robust and secure locking mechanism. You gain a more rigid connection between your lens and filter wheel, minimizing tilt and ensuring your optical train remains perfectly collinear throughout an imaging session, even with heavier telephoto lenses.

    • Rigid Connection: Reduces the potential for flexure and optical tilt compared to the first-generation model.
    • Secure Mounting: Confidently attach heavy lenses without worrying about slippage or unwanted rotation.

    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 EOS lens to a ZWO Electronic Filter Wheel (EFW), which is then connected to a ZWO camera with 6.5mm of back focus. It creates the correct 17.5mm spacing 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.

    What is the main improvement in this second-generation ZWO EFW-EOS adapter?

    The key improvement is a redesigned, more secure locking mechanism. This ensures a tighter, more rigid connection to the Canon lens, which is critical for preventing optical tilt and flexure, especially when using heavier telephoto lenses.

    Can I control the aperture of my Canon EOS 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 EOS
    Camera Side Connection ZWO EFW (Electronic Filter Wheel)
    Required Camera Back Focus 6.5 mm
    Resulting System Back Focus 17.5 mm
    Product Type Filter Wheel Adapter

    • Short EOS Adapter for EFW (Gen II)

      × 1

  • ZWO 2-Year Limited Warranty