Designed for astrophotographers seeking efficiency, the ZWO EFW 8 x 1.25-inch Electronic Filter Wheel allows for seamless, automated transitions between LRGB or narrowband filters. Weighing only 400g and featuring an ultra-thin 20mm body, this unit integrates easily into complex imaging trains without adding significant weight or bulk. Inside, a high-quality Japanese NPM stepper motor ensures precise filter positioning and quiet operation, essential for capturing long-exposure deep-sky images without vibration.

Connectivity is streamlined through a single USB 2.0 cable which powers the unit and handles data, drawing minimal power to preserve your battery life in the field. This device can be plugged directly into the USB hub of a ZWO cooled camera, significantly reducing cable clutter. Optimised for performance, the design keeps the filter close to the sensor—approximately 10mm with cameras like the ASI1600—minimising vignetting even when using fast focal ratios down to f/5 with 1.25" filters or f/2 with 31mm unmounted filters.

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

Lightweight & Rigid
Built for endurance, the new EFW utilises a CNC-machined aluminium alloy body for a lighter, more rigid structure. The internal filter carousel, crafted from 6061 aluminium alloy, reduces overall weight while maintaining the strength required for smooth, accurate rotation.

 
 

Automated Filter Switching
The new 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

• Versatile Filter Capacity: Accommodates up to eight 1.25" mounted or 31mm unmounted filters, making this ZWO Electronic Filter Wheel adaptable for complex imaging.

• Ultra-Thin Profile: The 20mm body thickness and lightweight design ensure easy integration into your optical train.

• Precision Stepper Motor: Utilises a high-quality Japanese NPM motor to ensure reliable and quiet operation of the electronic filter wheel.

• Single Cable Operation: Powered via a single USB 2.0 cable, simplifying cable management by connecting directly to your camera hub.

• Minimised Vignetting: The short distance between filter and sensor reduces vignetting, a key benefit of the ZWO filter wheel design.

 

What's in the Box

• EFW Body (8-Position)

• 1.25" Cover

• T2 Nosepiece

• 1.25" Holder (with cover and screws)

• T2-T2 Adapter (Male)

• Bag of Filter Masks

• USB 2.0 Cable (2m)

• Phillips Screwdriver

• Bag of M2 Screws

 

 

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	8 x 1.25" or 8 x 31mm (unmounted) filters
Thickness	20mm
Weight	400g
Power Supply	USB 2.0 (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!

	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-8x1.25