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ZWO Electronic Filter Wheel EFW Gen2 - 7 x 2"
ZWO Electronic Filter Wheel EFW Gen2 - 7 x 2"
ZWO Electronic Filter Wheel EFW Gen2 - 7 x 2"

ZWO Electronic Filter Wheel EFW Gen2 - 7 x 2"

by ZWO
SKU ZWO-EFW-7x2-25
Save 9% Save 9%
CA$559.00
CA$559.00 - CA$559.00
CA$559.00
CA$506.00
CA$506.00 - CA$506.00
CA$506.00
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  • Holds seven 2" mounted or 50.4mm unmounted filters
  • Adds 20 mm of back focus to the imaging train
  • Stepper motor for precise, quiet filter selection
  • Single USB-C cable for power and data
  • Directly compatible with ZWO full-frame and APS-C cameras
4 in stock
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • ZWO 7 Position Electronic Filter Wheel for 2" Filters (2025)

    The ZWO Electronic Filter Wheel EFW Gen2 holds up to 7 different 2" filters, adding only 20 mm of back focus to your imaging train. This capacity allows you to load entire LRGB and SHO filter sets simultaneously, selecting between any of the 7 positions via a single USB connection for fully automated imaging sequences.

    7-Position Carousel for 2" Filters

    The primary function of the EFW Gen2 is its 7-position capacity, which eliminates the need to swap filters manually between imaging sessions. You can install a complete LRGB color set (Luminance, Red, Green, Blue) and a narrowband SHO set (Sulfur-II, Hydrogen-alpha, Oxygen-III) at the same time, with one slot to spare. This is ideal for monochrome imagers who operate remotely or want to capture different data types on the same target in one night without reconfiguring their optical train.

    Engineered for a 20 mm Back Focus Path

    This filter wheel consumes exactly 20 mm of back focus, a critical measurement for planning a correct and rigid imaging train. The body is designed for direct, secure attachment to ZWO APS-C and full-frame cameras, creating a zero-flexure connection. The M54 threads on both the telescope and camera side maintain a wide, unvignetted light path suitable for large sensors, while the included M54-to-M48 and M54-to-M42 adapters ensure compatibility with a wide range of correctors and accessories.

    ZWO EFW Gen2 7 x 2" vs. 5 x 2"

    The main advantage of the 7-position EFW over its 5-position sibling is capacity. While both models share the same 20 mm back focus consumption and robust stepper motor design, the choice depends entirely on your imaging workflow.

    • ZWO EFW 7 x 2": Choose this model if you frequently switch between broadband (LRGB) and narrowband (SHO) imaging. The 7 slots let you keep both sets installed, making it perfect for automated, multi-night projects on galaxies that have H-alpha regions, like Andromeda (M31) or Triangulum (M33).
    • ZWO EFW 5 x 2": A more compact and lighter option, the 5-position wheel is sufficient if you primarily stick to one filter set per session, such as LRGB for galaxies or a dedicated narrowband palette for nebulae. It's a better fit for portable setups where weight and balance are primary concerns.

    USB-Powered Stepper Motor Control

    A high-precision stepper motor drives the filter carousel, ensuring positional accuracy and quiet operation. The wheel is powered and controlled through a single USB-C cable connected to your camera's USB hub or directly to your control computer. It is fully supported by the ASIAIR ecosystem and has ASCOM drivers for use with third-party software like NINA or Sequence Generator Pro, enabling seamless integration into automated imaging plans.

  • What types of filters can I install in the ZWO EFW 7 x 2"?

    The ZWO EFW 7 x 2" accepts standard 2" mounted filters with M48x0.75 threads. It can also hold unmounted 50.4 mm filters. This versatility covers the vast majority of astronomical filters from all major manufacturers, making it suitable for full-frame sensors without vignetting.

    Can I install both LRGB and SHO 2" filter sets in the ZWO EFW 7 x 2" at the same time?

    Yes. An LRGB filter set requires 4 slots, and an SHO narrowband set requires 3 slots. The 7-position carousel of the ZWO EFW 7 x 2" allows you to install both complete sets simultaneously, which is one of its primary advantages for advanced monochrome imaging.

    How does the 20 mm back focus of the ZWO EFW 7 x 2" affect my imaging train?

    The 20 mm back focus consumption is a fixed distance you must account for in your optical train calculation. For a typical setup requiring 55 mm of back focus, if your ZWO camera has 17.5 mm of native back focus, the EFW (20 mm) and any required adapters must total the remaining 17.5 mm. The included adapters are designed to help achieve this standard spacing with ZWO cameras.

    Is the ZWO EFW 7 x 2" compatible with non-ZWO cameras?

    Yes. While it's designed for direct connection to ZWO cameras, the filter wheel uses standard M54x0.75 threads on its telescope-facing side and includes M54M-to-M48F and M54M-to-M42F adapters. This allows you to connect it to a wide variety of cameras and optical systems that use these common T-thread standards.

    Does the ZWO EFW 7 x 2" require a separate power cable?

    No. The ZWO EFW 7 x 2" is powered directly via its USB connection. You can plug it into the integrated USB hub on a cooled ZWO camera or directly into your ASIAIR or control computer. This simplifies cable management at the telescope.

    How do I control the ZWO EFW 7 x 2" for imaging the Orion Nebula (M42)?

    You can control the filter wheel using software like the ZWO ASIAIR, NINA, or Sequence Generator Pro. For a target like the Orion Nebula (M42), you would create an imaging plan that automatically rotates to your H-alpha filter for capturing the core nebulosity, then to your LRGB filters to gather broadband data for the surrounding stars and dust, all without manual intervention.

  • SKU ZWO-EFW-7X2-25
    Product Type Electronic Filter Wheel
    Filter Size 2"
    Filter Positions 7
    Back Focus Consumption 20 mm
    Power Source USB
    Filter Mounting Threaded or Drop-In
    Warranty 2 Years

    • 7 Position Electronic Filter Wheel for 2" Filters (2025)

      × 1

    • M54M to M48F 2 mm Adapter

      × 1

    • M54M to M42F Adapter Ring

      × 1

    • M54M to M48F Adapter Ring

      × 1

    • M2.5x6 Screws

      × 6

    • M2x4 Screws

      × 26

    • Filter Masks

      × 10

    • 2 M USB-C Cable

      × 1

    • 0.5 M USB-C Cable

      × 1

    • Philips Head Screwdriver

      × 1

  • ZWO 2-Year Warranty