ZWO EFW (5 x 2″/7 x 2″)



Product Description

ZWO EFW (5 x 2″or 7 x 2″)

Product weight: EFW 5 x 2″=500g / EFW 7 x 2″=650g

Power supply: USB2.0

Control Mode: ASCOM and SDK

Driver: Free of driver


The filter wheel body is CNC milled from an aircraft graded aluminum block.

Excellent craftsmanship, very thin and light with only 20mm thickness.

The core part of our EFW is the stepper motor which has reliable performance and quality that comes from NPM, Japan.

We have two specifications for EFW2”:

  2″ Thread-In Filters or

50.4mm ±0.5mm Unmounted Filters can be used 

The 2” Electronic Filter Wheel can be rotated in both counter clockwise and clockwise direction for filter selection.

EFW2-2 EFW2-3

There is no need of multiple cables to power this wheel up, just one USB cable does the trick.The maximum power supply of this EFW is approximately 120mAh @ 5V, which can be operated from the Cooled CCD’s USB2.0 port.

When connected to ASI6200, the distance from the filter to the sensor is about 18mm

Our 2″ RGBL filters are recommended to work with ASI6200MM Pro camera, it will offer nearly 1:1:1 RGB color balance.


Below requirements must be met while using the 2” filter from third-party.

Requirements for 2inch filter from third party

Filters (not including the threads) must be less than 7.5mm in thickness and less than 50.8mm in diameter. Threads must be less than 2.7mm in thickness.


What’s in the box? 

1.EFW2*5 or FW2*7 body
2. USB2.0 – 2m cable
3. A bag of M2.5*6 screws (6pcs/ bag)
4. A bag of filter masks for 50mm filters (7pcs/ bag)
5. Phillips screwdriver
6. A bag of M2*4 flat screws (23pcs/ bag)
7. M54M-M48F adapter
8. M54M-M42F adapter
9.Darkening rings sets(4pcs)

Specifications for the darkening sets:

External diameter: 88mm. Inner diameter: 55mm (2pcs) & 58mm (2pcs). Thickness: ≤0.2. 4pcs in total.
*The reason for including the darkening sets is to help solve the light leaking issue occurring in the gap of the filter wheel and camera.

How to install the darkening sets: 

Mechanical drawing

EFW2X5-Mechanical drawing(1) EFW2X7-Mechanical drawing(1)

Usage guider:

5 connection methods of ASI6200 to get 55mm back focus length:


Q & A

1. My EFW tries to move but gets stuck and cannot arrive at the right position.

1) Filter is too thick: Filters (not including the threads) must be less than 7mm in thickness and threadsmust be less than 3mm in thickness.

2) The M2 screw used to secure the filter is too long and causes the wheel to jam.

3) The M42 thread of the scope or the camera is too long and protrudes into the filter wheel, hitting the filter or wheel, causing it to jam.

2. My EFW spins but never stops, or stops at the wrong position.

ZWO EFW uses an infrared sensor to check wheel position.  If the sensor malfunctions, you can usually resolve by recalibrating the EFW in the ASCOM driver. Simply click “ReCalibrate” in ASCOM driver interface. It can take up to 60 seconds to perform this action.

ASCOM Driver

3. I use 7-position EFW, normally I had slots 1, 2, 3, 4 filled and slots 5, 6, 7 empty, but then I got the error below and the EFW stopped working. I checked the carousel. It was not too tight or loose.


When using the filter wheel it is very important to keep its internal balance. The weight and distribution of the filters will affect balance. Thus we recommend you space the filters out and evenly distribute them. In this case, install them in slots 1, 3, 5 and 7, then the EFW will work again.

Our website is continuously updated with the most recent camera drivers as well as software for DSO and planetary imaging. Please make sure the most recent Driver and software have been installed before you start shooting:

It is also recommended to read the Manuals first before shooting.

Shipping & Delivery

Fast Shipping: we will choose DHL, UPS, FedEx etc to deliver it. Usually you will get your package within 15-20 days.

  • Fast Shipping(amount ≧ 199USD) for free
  • Fast Shipping(amount < 199USD) : $30.00 (We do not provide free shipping from now on.)


  1. It will take around 60-90 days for shipment via ePacket/China Post Registered Air Mail/EMS, which can’t be guaranteed due to force majeure. If you can’t get the air mail package after 2months, please let us know ASAP:
  2. Customers from Brazil and Chile should leave a message to provide your CPF or CNPJ as your custom needs it.
  3. Customers from Russia need to provide the complete English name with three words as well as the English shipping address.

Tracking site


China air mail:



  • The price list on our website is USD without tax.
  • Please note that buyers are liable to pay tax involved, such as Import tax, VAT , customs handling fee, etc. The additional fees may be collected at time of delivery by courier.
  • For best local service we advise customers buy our cameras from local dealers.


Warranty & Return

1. ZWO hereby declares that it will provide customers with a warranty period of 2 years for ZWO branded products (excluding APO), as per this policy. APO products will be covered by a 1-year free warranty service, starting from the day following the receipt of the product by the customer. For ASIAIR Plus users, the warranty period will commence from the day of device activation.

2. If a User encounters the following Dead on Arrival (DOA) and contacts ZWO within the corresponding time limit to issue the Product purchase invoice and relevant evidence, ZWO will provide door-to-door pick-up service and, as appropriate, after-sale replacement (or partial replacement), repair or return (or partial return) service for the following Products:
1) Product quality problem
Provided that a User detects a quality problem and contacts ZWO within 30 days after receipt of the Products, and ZWO support team confirms that the Products indeed have a quality problem or defect after their inspection, ZWO will provide free replacement service towards such Products;
2) Product transportation problem
Provided that a User finds obvious signs of bubbling, serious overstocking, or deformation on the outer package of the Products upon receipt of the Products, and provides ZWO with pictures of the outer package and proof of receipt within 3 days after receipt of such Products, ZWO support team will verify the actual shipper and determine the responsible party for such transportation problem. In the event that ZWO is the actual shipper, ZWO will be responsible for providing the relevant return or replacement service, however, if the Products are directly sold or transported to the User by an agent of ZWO, the agent will be responsible for providing the relevant return or replacement service.

3. If the Products are under the following circumstances, they are not within the scope of warranty service, ZWO may provide maintenance services to the Users:
1) The Warranty Period of the Products has expired; or
2) The Products are injected into liquid or affected by moisture or corrosion; or
3) The Products are damaged by an external force (such as the broken of the camera protection window glass, the deformation of the product shell, the broken of the USB port, etc.); or
4) Disassembling, repairing by a third party, refurbishment of the Products (such as downloading erroneous firmware) without the written authorization of ZWO; or
5) The product system is modified, or the maintenance notice is lost or changed; or
6) Product quality problem caused by installation not following the requirements or instructions for the Products; or
7) Physical damage or failure of the Products caused by the force majeure (such as strong vibration or extrusion such as flood, fire, earthquake, or thunder stroke); or
8)Damage caused by the improper User operation during the period of shooting or use, such as using without the equipment protection or direct shooting of the sun; or
9) No valid purchase invoice or warranty certificate; or
10) The Products are second-hand products.
Any quality problem with the accessories or other parts of the Products is not a condition for the return or change of the Products, and the User may solely request to replace the accessories with new ones, which shall be handled after verification by ZWO support team.
If the issue with your ZWO product was caused by certain damage (such as severe damage not covered by the 2-year warranty), you might have to pay the replacement value.

4. For the normal repair or replacement of the Products during the Warranty Period, the User will bear the return cost. When returning the Products, Users shall specify the actual reasons for the damage to the Products, and shall provide the corresponding valid certificates, such as pictures or videos, etc.
For the Products that need to be replaced after being confirmed by ZWO in writing, the User shall return the Products with the complete package, together with all accessories, manuals, etc., to the address designated by ZWO.
By sending back the product to ZWO, the User agrees to pay out-of-warranty fees that may arise during the repair process of the product. ZWO will send back the product after charging.

5. If a User encounters any problem during the use of ZWO Products, you may at any time contact ZWO for technical support via ZWO Support.

For the Products that need to be returned for after-sales service, ZWO will provide the corresponding RMA code for reference.
ZWO will not accept any products having no RMA code that have been returned privately without ZWO written confirmation.

6. If a User purchases the ZWO Products from a ZWO agent, the User may contact the ZWO agent directly for the relevant after-sales service.

Do you have question, answer or comment? Post here!

  1. Avatar


    I want to buy 5×2″.
    I use f2.8 newtonian tube. I also use Sony A7S2 as a camera. The tube has M48 connection. For the camera, I use the M48-E mount adapter.
    Can I integrate this product into the system I have without any problems?


    • Avatar


      Hello, I think it is no problem.


  2. Avatar


    Will the 7×2 EFW work with a ASI 183 Pro Mono and ASI 071 OSC Pro?


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      Hello! Can you tell me what telescope you are using?


  3. Avatar


    Hello, I want to buy it. Can I also pay with credit card? You only offer paypal and I don’t want this.



  4. Avatar


    hello, how to fix my asi533 mc pro camera on the efw 5*2inch?


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      Hello! Is your issue resolved? If not, please email us at with further details. If your issue has been resolved or if you have any other questions, feel free to contact us anytime. Thank you for your message and support!


  5. Avatar


    Need help, just got my zwo 5 position filter wheel, it connects, but just spins in a circle and when it lands it’s in between filters or totally wrong, I tried somethings online to do by adjusting the center screw, it will not recalibrate, please help I would like to be able to use this I just spent 299.00 right out of the box it doesn’t work right.


    • Avatar


      Hello! We apologize for this inconvenience. Please contact our support( They have the expertise and resources to assist you effectively.


  6. Avatar


    Hi guys,
    In the description it says:
    “When connected to ASI6200, the distance from the filter to the sensor is about 18mm”

    Is that 18mm distance when the tilt plate is still attached or only if it’s removed?
    If 18mm is the distance when the tilt plate is still attached then that only allows an extra 0.5mm for the filter wheel back plate & the internal space to the actual filter. Or am i missing something.. thanks.


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    Can be this fw connected directly with camera ASI2600mm with crews, or it is just for full frame 6200 ?


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      For both 2600mm and 6200.


  8. Avatar


    I can not figure out how to connect my new ZWO ASI071MC Pro to my new ZWO 5 X 2″ EFW. Please explain how to do this.


  9. Avatar


    You specify for unmounted filters 50.4 +/- 0.5mm. The Astrodon filters have a diameter of 49.7mm. According to your specification they won’t fit. Is that correct?


    • Avatar


      It can fit but maybe a little loose which can be ignored.



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