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ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square
ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square
ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square
ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square
ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square
ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square
ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square
ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square
ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square
ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square

ZWO Electronic Filter Wheel EFW Gen2 - 7 x 50mm Square

by ZWO
SKU ZWO-EFW-7x50-26
$599.00 - $599.00
$599.00
$599.00 - $599.00
$599.00
Price Match Policy!
  • Holds 7 individual 50mm square filters
  • Designed for large format monochrome cameras like the ASI461MM Pro
  • Adds only 16mm of optical path length to the imaging train
  • Upward-facing USB Type-C port
  • Directly bolts to the ZWO OAG-L-68 large off-axis guider
  • Powered and controlled through a single USB connection
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • ZWO Electronic Filter Wheel EFW-7x50-26 - 7 x 50mm Square

    The ZWO Electronic Filter Wheel EFW-7x50-26 is engineered to automate filter changes for large-format imaging, holding 7 different 50mm square filters in a rigid, CNC-machined aluminum body. It adds a minimal 16mm of optical thickness to your imaging train, ensuring back focus can be precisely managed. This updated -26 model replaces the discontinued EFW-7x50, now with an upward-facing USB Type-C port.

    7-Position Carousel for 50mm Square Filters

    Designed specifically to prevent vignetting on large-format sensors, this filter wheel accommodates seven unmounted 50mm x 50mm square filters with a supported thickness from 3mm to 4mm. The internal carousel is driven by a high-precision NPM stepper motor from Japan, allowing for precise, reliable and bidirectional filter selection. This capacity lets you load a full LRGB and narrowband filter set for imaging sessions without manual filter changes.

    Direct-Bolt Integration and a 16mm Optical Path

    The EFW-7x50-26 creates a solid imaging train by bolting directly to the camera body of the ZWO ASI461MM Pro and the telescope side of the ZWO OAG-L-68. The wheel contributes a fixed 16mm of optical path length, a critical and known value that simplifies back focus calculations for your entire system.

    EFW-7x50-26 vs. EFW-7x50: Upward-Facing USB-C

    This -26 model is a direct replacement for the previous EFW-7x50, with a revised USB interface and housing. The main changes ZWO lists are:

    • Upgraded Port: The original side-facing USB port has been replaced with an upward-facing USB Type-C port.
    • Streamlined Housing: The slots on the sides of the housing, which previously accommodated the side port, have been removed.
    • Cable Requirement: This new version requires a standard USB Type-C cable for power and data; the original USB cable is no longer compatible.

  • What is the primary purpose of the ZWO EFW-7x50-26?

    The ZWO EFW-7x50-26 is designed for advanced astrophotographers using large-format monochrome cameras, such as the ZWO ASI461MM Pro. It automates the process of switching between up to 7 different 50mm square filters (e.g., LRGB, Ha, SII, OIII) without needing to touch the telescope, enabling fully remote or scripted imaging sessions.

    What filters are compatible with the EFW-7x50-26?

    This filter wheel is made for 50mm x 50mm square unmounted filters. It is optimized for filters that are 3mm thick, but the internal mechanism can support a thickness range from 3mm to 4mm.

    How does the 16mm optical length of the EFW-7x50-26 affect back focus with an ASI461MM Pro?

    The 16mm optical length is the amount of back focus the filter wheel itself uses. Add it to the camera's own back focus and the thickness of the ZWO OAG-L-68, then make up the rest of the distance your flattener or reducer needs with spacers.

    Does the ZWO EFW-7x50-26 require an external power supply?

    No. The EFW-7x50-26 is powered and controlled entirely through its single USB Type-C connection. It can be connected to a computer, a ZWO ASIAIR, or the USB ports of a ZWO ASI cooled camera.

    Why are 50mm square filters important when imaging the Cygnus Loop (NGC 6960) with a fast astrograph?

    A large target like the Cygnus Loop, imaged with a large sensor and a fast optical system (e.g., f/4 or f/5), produces a steep light cone. Smaller 2-inch round filters would cause significant vignetting, darkening the corners of the image. The 50mm square format of the EFW-7x50-26 provides a large clear aperture needed to fully illuminate the sensor, ensuring even brightness from edge to edge.

    What software can I use to control the ZWO EFW-7x50-26?

    The filter wheel is compatible with a wide range of software. It works seamlessly with ZWO's own ASIAIR controllers and ASIStudio software. It is also supported through ASCOM and the ZWO SDK, so it works with ASCOM-compatible capture programs.

  • Model EFW-7x50-26 (replaces the discontinued EFW-7x50)
    Filter Positions 7
    Supported Filters 50 x 50 mm square unmounted filters, 3 mm thick (3 to 4 mm supported)
    Optical Path Length 16 mm
    Body Construction CNC-machined aircraft-grade aluminum
    Motor NPM (Japan) stepper motor, bidirectional rotation
    Connectivity Upward-facing USB Type-C
    Power USB powered, no external power supply
    Control ASIAIR, ASCOM, and ZWO SDK
    Driver Driver-free
    Camera Side Connection Bolts directly to the ZWO ASI461MM Pro
    Telescope Side Connection Bolts to the ZWO OAG-L-68 large off-axis guider
    Diameter 239 mm
    Weight 1190 g
    Warranty 2 years

    • EFW-7x50-26 Filter Wheel

      × 1

    • 2.0 x 75 mm Phillips Screwdriver

      × 1

    • 50 x 50 mm Filter Masks

      × 10

    • Darkening Rings Set

      × 1

    • M2.5 x 6 Screws

      × 12

    • M2 x 4 Screws (26 pcs per bag)

      × 2

    • 2 m USB 2.0 Right-Angle Cable

      × 1

    • 0.5 m USB 2.0 Right-Angle Cable

      × 1

  • ZWO Warranty