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ZWO EFW 7x2-inch Electronic Filter Wheel
The ZWO EFW 7 x 2-inch Electronic Filter Wheel is the ultimate convenience upgrade for full-frame imaging, allowing you to keep seven filters installed at once. With a whisper-quiet motor and robust construction, this electronic filter wheel makes automating complete LRGB and narrowband sequences effortless.
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For astrophotographers moving to full-frame cameras, the ZWO EFW 7 x 2-inch Electronic Filter Wheel is the piece of gear that makes the whole system click. With seven filter positions, it solves the common frustration of having to swap out carousels or filters manually between targets. You can load a full set of LRGB and SHO (Sulphur, Hydrogen, Oxygen) filters at once, allowing you to capture broadband galaxies and narrowband nebulae in the same session without ever touching your telescope. It’s about setting up your imaging sequence once and letting the equipment do the rest while you sleep.
Mechanically, this ZWO EFW is built to handle the larger light path required by massive sensors like the Sony IMX455 found in the ASI6200. By using wide M54 connections on both sides, it ensures that light reaches the very corners of your sensor, eliminating the heavy vignetting you would typically get with smaller connections. Despite being CNC-machined from aircraft-grade aluminium for rigidity, ZWO has kept the profile surprisingly slim at just 20mm, helping you fit it into tight back-focus spacing. It runs off a single USB cable connected to your camera’s hub, keeping your cable management clean and your setup reliable.
Anti Light-Leak Design
In deep-sky imaging, stray light is the enemy. The new ZWO EFW introduces a re-engineered slot-fit chassis and dual light-blocking pads on lateral connection points to create a superior optical barrier. Combined with a fully sealed motor compartment, this design minimises potential ingress points, helping you maintain clean, uniform frames during long integrations.
Interface Upgrade
Reliability meets modern connectivity. The next-generation EFW replaces the legacy USB Type-B connector with a robust USB-C interface. This upgrade simplifies cable management with reversible plugging and ensures a more stable data connection for your imaging system.
Compact & Lightweight
The 5-position EFW is the smallest wheel in the ZWO lineup. Crafted from CNC-machined aircraft-grade aluminium, it is incredibly rigid yet weighs approximately 300g. This featherweight design is ideal for portable rigs and smaller refractors where keeping weight down is critical.
Automated Filter Switching
The ZWO EFW features a motorised, bidirectional filter-wheel drive with precise position indexing. When paired with control software such as ASIAIR (sold separately), it enables automatic filter changes during a scheduled imaging session — enabling fully unattended, hands-free astrophotography.
Key Features
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Complete Filter Set: Holds up to seven 2-inch mounted or 50.4mm unmounted filters, allowing for permanent installation of full LRGB and Narrowband sets in one ZWO EFW.
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Vignette-Free: The large filter format and M54 interface provide a wide light path, essential for clear imaging on Full Frame Filter Wheel setups.
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Precision Drive: A high-quality Japanese NPM stepper motor ensures filter changes are fast, accurate, and virtually silent.
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Built to Last: CNC-machined from aircraft-grade aluminium for a rigid, light-tight housing that supports heavy cameras with ease.
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Plug-and-Play: Powered and controlled via a single USB 2.0 cable (approx 120mA), which can be powered directly from your camera's USB hub.
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Slim Profile: Maintains a 20mm optical thickness to help you stay within back focus limits on complex optical trains.
What's in the Box
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EFW 5 x 2" Body
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M54M-M48F Adapter
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M54M-M42F Adapter
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M54M-M48F-2 Adapter
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Bag of Filter Masks (10 pcs)
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USB 2.0 Cable (2m)
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USB 2.0 Cable (0.5m)
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Phillips Screwdriver (3x75mm)
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M2.5*6 Screws (6 pcs)
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M2*4 Screws (26 pcs)
How to Use the EFW
To operate the electronic filter wheel, simply connect it using a USB 2.0 cable and install the ZWO ASCOM driver. Within your imaging software, select either “ZWO Filter Wheel (1)” or “ZWO Filter Wheel (2)”—both options work identically and are designed to support multiple filter wheels in a single setup.
How to connect the camera and telescope:
Specifications
| Number of Positions | 7 x 2" threaded or 7 x 50.4mm (unmounted) filters |
| Thickness | 20mm |
| Weight | ~650g |
| Power Supply | USB Power (120mA max @ 5V) |
| Motor | Stepper |
| Material | CNC-machined aircraft-grade aluminium |
| Thread Interface | M54 x 0.75 (Input and Output) |
| Compatibility | Ideal for ZWO cooled cameras |
| Vignetting Limits | 2" filters down to f/5, 50.4mm filters down to f/2 |
Recommended Accessories
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ZWO NEW 1.25-inch LRGB Filter Set Get started with monochrome astrophotography by using these dedicated filters to separate light into LRGB wavelengths for better detail. |
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ZWO Narrowband 7nm 1.25-inch Filter Set Get started with SHO imaging with the ZWO Narrowband 1.25" Filter Set. Narrowband filters improves contrast between nebulae and reduces effects of light pollution. |
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ZWO 850 IR 1.25-inch Filter Add a IR-Pass filter to enhances contrast in planetary imaging (great for Mars, Jupiter, Moon). |
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ZWO ASIAIR Plus - 256GB Model Control your new astronomy camera with the ZWO ASIAIR Plus. This device enables you to control, guide, filter control and power your camera without using a computer. Perfect for streamlining and cord management! |
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About ZWO Optical
Established in 2011, ZWO Optical is a fast-growing global astroimaging camera powerhouse based in Suzhou, China. Known for its iconic ZWO ASI 120MM Monochrome CMOS Camera, the first-ever planetary CMOS camera to beat a CCD in the early 2010s, ZWO has pioneered new astroimaging technology with revolutionary new features, including USB 3,0, cooled systems, ADC and more. Today, ZWO Cameras is known by every passionate astrophotographer and is available in over 25 countries world-wide.
Product Code: ZWO-EFW-7x2-25
| Image | Item | Qty |
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EFW 5 x 2" body | 1 |
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M54M-M48F Adapter | 1 |
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M54M-M42F Adapter | 1 |
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M54M-M48F-2 Adapter | 1 |
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A bag of Filter Masks | 10 |
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USB2.0 Cable 2m | 1 |
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USB2.0 Cable 0.5m | 1 |
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Phillips Screwdriver | 1 |
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M2.5*6 Screws | 6 |
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M2*4 Screws | 26 |
Q1. What is the ZWO EFW 7 x 2" Electronic Filter Wheel used for?
The ZWO 7-position 2-inch electronic filter wheel allows you to automatically switch between up to seven 2-inch filters. It is designed for advanced astrophotographers using Full Frame cameras who want to install a complete set of filters (such as LRGB and SHO narrowband) simultaneously without needing to manually swap them.
Q2. What filters are compatible with the ZWO EFW 7 x 2" filter wheel?
It supports both 2-inch threaded filters and 50.4mm unmounted filters. This flexibility allows you to use standard screw-in filters or professional unmounted glass depending on your preference.
Q3. What is the advantage of the 5 x 2" filter wheel?
The primary advantage is capacity. With 7 slots, you can hold a full LRGB broadband set plus a complete narrowband set (H-alpha, SII, OIII) in a single unit. This allows you to image any target—whether a galaxy or a nebula—without ever touching the telescope to change filters or re-shoot flat frames.
Q4. How is the ZWO EFW 7 x 2" powered?
It requires no external power supply and is powered entirely via a single USB 2.0 cable. Power consumption is low at approximately 120mA @ 5V, so it can be powered directly from the USB hub on a cooled camera to keep cabling tidy.
Q5. Is the ZWO EFW compatible with ASIAIR and ZWO cameras?
Yes, the ZWO EFW is fully compatible with the ZWO ASIAIR series and all ZWO cooled astronomy cameras. It seamlessly integrates into the ZWO ecosystem for automated imaging.
Q6. How do I control the ZWO EFW 7 x 2"?
The filter wheel is controlled via USB using ZWO’s ASCOM drivers. Most astrophotography software such as NINA, Sequence Generator Pro, MaximDL, and the ASIAIR app supports the filter wheel.
Q7. Will the ZWO 7 x 2" filter wheel cause vignetting?
No. Like the 5-position version, this wheel is engineered to prevent vignetting on large sensors. It uses 2-inch filters and wide M54 threads to provide sufficient light throughput to cover a Full Frame sensor.
Q8. Is the ZWO EFW 7 x 2" easy to install and use?
Yes, despite its larger capacity, it maintains a slim profile (20mm thickness). It uses M54 threads on both sides to maximize the light path for large chips, but it is supplied with adapters to fit M48 or M42 threads for easy integration with most optical trains.
Q9. What is included with the ZWO EFW 7 x 2"?
The package includes the filter wheel body, USB cable, M54 adapters (M54M-M42F and M54M-M48F), filter masks, screws for unmounted filters, and a screwdriver.