The ZWO EFW 5 x 2-inch Electronic Filter Wheel is the heavy-duty answer for astrophotographers moving up to full-frame cameras or larger optical systems. Unlike smaller wheels that can restrict light at the corners of a large sensor, this unit is engineered with wide M54 connections and holds up to five 2-inch threaded or 50.4mm unmounted filters. This design ensures that massive sensors, like the IMX455 found in the ASI6200 series, receive uniform illumination, letting you capture the full field of view without worrying about heavy vignetting. Despite handling larger glass, ZWO has kept the profile surprisingly slim at just 20mm, so it fits neatly into your back-focus calculations without adding unnecessary bulk.

Reliability is key when your gear is running all night, and this wheel uses a high-quality Japanese NPM stepper motor to ensure every filter change is precise and whisper-quiet. Cable management is kept tidy with a single USB 2.0 cable that handles both power and data, plugging directly into the hub of your cooled camera so you don't have another cable dragging from your computer. Whether you use the ASIAIR system or PC software via ASCOM, this ZWO EFW integrates effortlessly, allowing you to set up your imaging sequence and let the gear handle the rest while you sleep.

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

• Full-Frame Ready: Accommodates up to five 2-inch mounted or 50.4mm unmounted filters, effectively preventing vignetting on large sensors.

• M54 Interface: Equipped with M54 threads on both sides to maximise the light path, a crucial feature for a high-performance ZWO filter wheel.

• Precision Motor: Powered by a Japanese NPM stepper motor for reliable, accurate, and quiet positioning of the electronic filter wheel.

• Robust Build: CNC-machined from aircraft-grade aluminium, ensuring a rigid, light-tight structure that weighs only ~500g.

• Single Cable Power: Runs entirely off USB 2.0 (120mA @ 5V), simplifying your setup by connecting directly to the camera hub.

• Slim Profile: The 20mm optical thickness minimises back focus consumption, making integration into complex optical trains easier.

 

 

What's in the Box

• EFW 5 x 2" Body

• M54M-M48F Adapter

• M54M-M42F Adapter

• M54M-M48F-2 Adapter

• Bag of Filter Masks (10 pcs)

• USB 2.0 Cable (2m)

• USB 2.0 Cable (0.5m)

• Phillips Screwdriver (3x75mm)

• M2.5*6 Screws (6 pcs)

• 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	5 x 1.25" or 5 x 31mm (unmounted) filters
Thickness	20mm
Weight	~300g
Power Supply	USB Power (120mA max @ 5V)
Motor	Stepper
Material	CNC-machined aircraft-grade aluminium
Compatibility	Ideal for ZWO cooled cameras and ASIAIR setups
Vignetting Limits	1.25" filters down to f/5, 31mm filters down to f/2

 

Recommended Accessories

	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.
	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.
	ZWO 850 IR 1.25-inch Filter Add a IR-Pass filter to enhances contrast in planetary imaging (great for Mars, Jupiter, Moon).
	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!

 

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: EFW-5x2-25