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July 1st: Store will be closed for Canada Day. Orders placed that day will ship on July 2nd.
ZWO Electronic Filter Wheel EFW Gen2 - 8 x 1.25"
ZWO Electronic Filter Wheel EFW Gen2 - 8 x 1.25"
ZWO Electronic Filter Wheel EFW Gen2 - 8 x 1.25"

ZWO Electronic Filter Wheel EFW Gen2 - 8 x 1.25"

by ZWO
SKU ZWO-EFW-8x1.25-25
CA$419.00 - CA$419.00
CA$419.00
CA$419.00 - CA$419.00
CA$419.00
Price Match Policy!
  • Holds 8 x 1.25" or 31mm unmounted filters
  • Adds 20 mm of back focus to the imaging train
  • USB-powered stepper motor for precise filter selection
  • Redesigned housing for improved light leak prevention
  • ASCOM and ASIAIR compatible for full automation
1 in stock
Qualifies for FREE Shipping in Canada on orders over $500.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • ZWO EFW 8-Position Filter Wheel for 1.25" and 31 mm Filters (2025)

    The ZWO EFW Gen2 automates your imaging sequence with an 8-position carousel designed for both 1.25" and 31mm filters. This USB-powered wheel consumes a minimal 20 mm of back focus, making it a straightforward addition to most optical trains while enabling full LRGB and narrowband filter sets to be loaded simultaneously.

    Automate 8 Filters for LRGB and SHO Sequences

    The 8-position carousel is the core of this wheel's efficiency, allowing you to load a complete LRGB filter set (Luminance, Red, Green, Blue) and a full SHO narrowband set (Sulfur-II, Hydrogen-alpha, Oxygen-III) with a position to spare for a UV/IR cut or dark filter. This capacity eliminates the need to swap filters between imaging sessions, enabling fully automated, multi-night projects controlled via ASIAIR or ASCOM-compliant software.

    A Consistent 20 mm Back Focus Path

    ZWO engineered this filter wheel to consume exactly 20 mm of back focus. This fixed optical path length simplifies the process of integrating it with reducers and flatteners that have strict spacing requirements. By maintaining a known, slim profile, you can calculate your adapter and spacer needs without the complexity introduced by bulkier filter solutions.

    Dual 1.25" and 31mm Filter Support

    The wheel is designed to accept both industry-standard 1.25" mounted filters and 31mm unmounted filters. This flexibility ensures compatibility with a vast range of filters from nearly every manufacturer, protecting your investment in glass. Whether you use threaded filters for convenience or unmounted filters to maximize the clear aperture for a specific sensor, the EFW Gen2 accommodates both formats securely.

    ZWO EFW Gen2 vs. First Generation

    This second-generation model introduces key structural improvements over its predecessor. The most significant is a redesigned housing that provides superior light leak protection, critical for long-exposure narrowband imaging. The internal stepper motor is also refined for quieter, more reliable operation, ensuring precise filter alignment every time without disturbing the telescope's balance.

  • How many filters can the ZWO EFW Gen2 8-position wheel hold?

    The ZWO EFW Gen2 8-position filter wheel is designed to hold up to 8 individual filters. It is compatible with both standard 1.25" mounted filters and 31mm unmounted filters.

    What is the back focus of the ZWO EFW 8 x 1.25" filter wheel?

    The filter wheel adds exactly 20 mm of back focus to your imaging train. This measurement is crucial for correctly spacing your camera sensor from any field flattener or focal reducer.

    Can I use the ZWO EFW 8-position wheel for an LRGB + SHO filter set with my ASI1600MM Pro?

    Yes, absolutely. The 8-filter capacity is ideal for this exact scenario. You can load a full LRGB set (4 filters) and a full SHO narrowband set (3 filters), leaving one slot free for a dark filter, a UV/IR Cut filter, or another specialized filter. This allows you to run fully automated sequences for both broadband and narrowband targets like the Orion Nebula (M42) without ever opening the imaging train.

    How do I power the ZWO EFW Gen2 filter wheel when connected to my imaging PC?

    The ZWO EFW Gen2 is powered directly via its USB connection. No separate 12V power supply is required. You can connect it to your ZWO cooled camera's integrated USB hub or directly to your ASIAIR, laptop, or control PC.

    Does the ZWO EFW Gen2 support both 1.25" mounted and 31mm unmounted filters?

    Yes, the wheel is designed to accept both formats. It uses screws to secure either the threads of a 1.25" filter cell or the edge of a 31mm unmounted filter disk, giving you flexibility in your filter choices.

    What improvements does the ZWO EFW Gen2 have over the previous version?

    The primary improvements in the Gen2 model are a redesigned body for enhanced light leak prevention and an upgraded stepper motor for quieter and more precise operation. These changes make it more robust for demanding long-exposure astrophotography where stray light and mechanical reliability are critical.

  • SKU ZWO-EFW-8X125-25
    Product Type Electronic Filter Wheel
    Filter Capacity 8 Positions
    Supported Filter Sizes 1.25" or 31mm
    Filter Mounting Accepts Both Threaded & Drop-In
    Back Focus Consumption 20 mm
    Power Source USB
    Warranty ZWO - 2 Years

    • 8-Position Filter Wheel Body

      × 1

    • M42M to M42M Adapter (T2 to T2)

      × 1

    • 1.25" Nosepiece

      × 1

    • 1.25" Camera Connection

      × 1

    • M2.5x6 Screws

      × 6

    • M2x4 Screws

      × 26

    • M4x12 Screws

      × 2

    • Filter Masks

      × 10

    • 2 M USB-C Cable

      × 1

    • 0.5 M USB-C Cable

      × 1

    • Philips Head Screwdriver

      × 1

    • 1.25" Cover & Cap

      × 1

  • ZWO 2-Year Warranty