ZWO EAF (Electronic Automatic Focuser) – Precision in Every Step

The latest generation of the ZWO EAF (Electronic Automatic Focuser), introduced in June of 2025, is a powerful upgrade for any astrophotography setup. Sleek, sturdy, and smartly designed, the new EAF combines refined engineering with real-world practicality. The EAF delivers consistent, micron-level precision in a compact package.

High-Torque, High-Precision Focusing

Inside the all-metal housing is a custom high-resolution stepper motor with a 1:128 reduction ratio. The result? Ultra-fine, micron-level positioning accuracy. Every movement of your focuser is repeatable, backlash-free, and reliable—ideal for fine-tuning focus on deep sky objects or achieving pinpoint sharpness in planetary imaging.

Compact but Strong – Supports 11 lbs

Despite weighing just 7.5 ounces (215g), the EAF can handle a load capacity of up to 11 lbs (5kg). It’s been tested to perform under heavy loads—like imaging setups with filter wheels, large cameras, or off-axis guiders—without slipping or stalling. If you need a compact solution with big-league muscle, this is it.

USB Type-C Interface – Smarter, Simpler

ZWO has upgraded the EAF’s interface to USB Type-C, giving you broader compatibility with modern devices and simplifying your cable management. Power and data flow through a single connection to your ASIAIR, imaging camera, or laptop—cutting clutter and making setup faster.

Compatible with ASCOM, INDI, and Popular Software

Whether you're a Windows user or running a Raspberry Pi under the stars, the EAF is ready. It works seamlessly with:

ZWO software: ASIAIR App, ASIStudio
Third-party platforms: SharpCap, FireCapture, Maxim DL, TheSkyX, Sequence Generator Pro (SGP), Nebulosity, and more
Also fully compatible with popular autofocusing tools like FocusMax

Optional Hand Controller (Sold Separately)

For those who prefer a more hands-on experience, the optional EAF hand controller (available separately) allows manual IN/OUT focusing without a computer or phone. Its simple interface helps reduce vibrations during operation, making it a helpful addition in the field.

Specifications:

Dimensions: 41mm x 52mm x 70.3mm
Weight: 7.5 oz (215g)
Load Capacity: 11.02 lbs (5kg)
Motor Type: Stepper motor, 7.5° step angle, 1:128 reduction ratio
Communication & Power: USB Type-C (5V 500mA)
Software Support: ASIAIR App, ASIStudio, ASCOM, INDI, FocusMax, and more

Observing Tip:
When using the EAF for long-exposure imaging, be sure to set a short pause after focusing to allow for any residual vibration to settle. This is especially useful when autofocusing with fast optics or heavy imaging trains.

Final Thoughts:
ZWO’s latest EAF takes everything that made the original a favorite—and makes it even better. With a Type-C connection, higher load capacity, and precision stepper motor performance, this compact focuser punches well above its weight. Whether you’re automating a portable setup or refining your observatory-grade rig, the new EAF is ready to keep things sharp.

Connecting your EAF

1. Remove the coarse adjustment knob of the telescope focuser using a suitable sized wrench.

2. Install the coupling on the telescope focuser shaft and tighten the locking screw with the 2mm hex wrench. 3. Attach the focuser body to the coupling, align the EAF motor shaft flat surface with the locking screw, and tighten the locking screw using the provided 2mm hex wrench.

4. Secure the EAF body to the bracket and the bracket to the matching mounting holes in the focuser assembly using the supplied M4 screws. Ensure that the bracket is flush with the EAF mounting surface without any gaps, and that it is parallel to the focuser body surface.

5. Check and ensure that all the connections of the EAF are secure. This completes the hardware installation of the EAF.

6. For curved focusers like the one in the image above, you only need to use wodethe original locking screws and 3 washers to secure the EAF. There is a groove at the bottom of the EAF bracket, and a single screw provides sufficient stability.

ZWO EAF Electronic Focuser

Tech Details:

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