Brand: ZWO

ZWO EAF 5V Electronic Automatic Focuser (ZWO-EAF-5V)


Brand: ZWO

ZWO EAF 5V Electronic Automatic Focuser (ZWO-EAF-5V)


The ZWO electronic auto focuser (EAF) is sure to improve your astrophotography sessions with pin-point stars. It's a great little package that can be installed on virtually any telescope.
  • Highly integrated design
  • Support ASCOM platform and various ASCOM-compatible third-party software
  • Support INDI
  • Support original software such as ASIAIR and ASIStudio
  • Support automatic focusing for DSO imaging
  • Support handle controller and manual focusing
  • Support temperature sensor
  • USB HID device and driver-free
  • Stable and durable
$269.00 CAD

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Why we love the ZWO EAF 5V Electronic Automatic Focuser (ZWO-EAF-5V)

The 5V EAF (ZWO-5V-EAF) automatically focusses your telescope for planetary and deep-sky imaging, while only connected to a 5V USB-port.  The EAF has several accessories available for it including a temperature sensor, a hand controller, and adapters for a number of optical tubes.  The EAF works seamlessly with other ZWO products, the ASIAIR will even allow you to control it with your phone.  These are a great device for new and experienced astrophotographers.  

Recommended Accessories

The EAF has a few accessories available for it.  The three that we really like pairing it with are:

1. The EAF Hand Controller will allow you to remotely adjust the focus of your telescope.

2. The Temperature Sensor for the ZWO EAF lets you automatically refocus based on changes in temperature. 

3. The ZWO ASIAIR isn't specifically an accessory for the EAF, but it does allow for easy integration and management of the EAF in your imaging system.  

These accessories can help you get the very best out of the ZWO EAF.

Product Description

This is the current version of the EAF. It no longer requires a dedicated 12V power supply. Now you can directly connect it to your camera, laptop or ASIAIR via the USB 2.0 port and use a cable for both data transmission and power supply! This makes the cable management much easier, as well as reducing the need for additional power outlets.

The innovative decorative pattern on the EAF is inspired by the changes of Airy disk during focusing showing how the focusing curve gives a local minimum at best focus – giving an easy explanation on how the EAF works just with a glance on the cover!


  • Size: 59mm x 52mm x 41mm
  • Motor: Step motor, 35mm diameter, 7.5° step angle
  • Reduction ratio: 120
  • Power/Data port: USB2.0 port, Type-B
  • Weight: 277g
  • Capacity: 5kg

Customer Reviews

Based on 28 reviews
Excellent product. Working as expected.

Just like a lot of their products from ZWO does an excellent job. I'm using it on my William Optics Zenithstar 81. I thought the installation would be rather complex, but surprisingly it is not. For me this automatic focuser is a must have, as there is too much vibration when trying to focus manually.

Easy to install, now for clear skies to try it

Installation was a breeze, works with both the hand controller and the ASI Air App.

Now, all I need is some clear skies to try it out, soon I hope (SSSP was a bit of a bust)

Best ASIAIR companion

This has simplified my life tremendously and it is plug and play with the ASIAir. I just love this. I have it on all my rigs now and I am enjoying the results. Quality made, installs on almost anything (you may have to buy a specific bracket for some scopes), and installs in minutes. i love this thing.

Outstanding value!

This little focuser is sturdily built, easy to set up, and excellent value. Couldn’t be happier.

I am using it with the ASI2600 and my Tak FSQ-106. The focuser comes with four flexible couplings, the largest of which was still too small for the Tak rack and pinion focuser. I easily drilled one out on a small drill press. The included mounting hardware is beefy and the focuser itself feels solid.

Performance is top notch as well. Directly attached to my R&P focuser, the movement of the tube is about 4 micrometers per step, which is awesome as my critical focus zone is about 60 micrometers. Once I measured the backlash and configured software to overshoot and return, the focus position is 100% repeatable.

This is a high quality accessory at a very affordable price.


Seems like a decent and well built item, a bit pricey but everything in AA is these days. In order to use it properly with an SCT and get the needed number of steps to run the whole focusing cylce I had to do the ZWO latest firmware update.

Overall I do think it is going to work very well for my needs, the biggest concern is cost.

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