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Wired Canon EF/EF-S lens adaptor for ASI294 camera.


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Hi All, 


My new project is a DIY version of this product. I have focus/aperture by wire lens for my Canon camera and I would like to use my ASI294mc with them especially  my 50 mm, 24 mm primes and  also my 250 mm zoom lens. 

I started with the following 3d printed adaptor (here) as a base. I modified it to enable pogo pins to fit and make contact with the pads on the lens.  I am now waiting for the small circuit board to adapt the pogo pins to a 2.54 mm header for ease of connection. 



Once I receive the circuit board I will be able to start writing the arduino code to interface with the lens. I have found the protocol online. As I teach arduino programming to students at a college, the program should be no problem. 



I plan the following specs:

1) Works with EF and EF-S (currently 3d model only fits EF as I need to chop a bit off.)

2) Be able to set aperture with two buttons, setting to be displayed on 0.9 inch LCD screen.

3) Be able to focus: 1 button for near focus, one for infinite focus, +/- 10 steps, +/- 1 step. (possibly include a routine that works out how many steps from near to far focus and then display on screen to enable more precise refocusing in subsequent sessions). 

I will update this page as  I progress. The adaptor will fit all astrocams with 17.5 mm back focus.IMG-0197.thumb.JPG.dac521c29eaa1f73c7cca46d44b5b22e.JPGIMG-0198.thumb.JPG.9a22c73bcaa603f80ce1c9c6373bee12.JPG



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  • 2 months later...

Finally managed to have time to progress this project. 

So far: 

1) Figured out the protocol and code to send commands and parse replies. 

2) I can adjust aperture and focus.

3) Implemented routine to find current focus position.

4) Implemented routine to move focus steps +/-.

5) Implemented routine to find total number of focus steps.


On the lens I am using the focus motor is not that precise.


Edited by chemistorge
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  • 3 weeks later...
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  • 1 month later...

Hi There, 


Sorry for the long time for a reply, work, christmas and Covid has got in the way.


I have wrote the basics of a arduino library for accessing EF and EFS lens. I have also wrote a sketch that can communicate with Ekos via the Myfocuser2 protocol, it allows you to do the autofocus routine with a canon lens.


I have attached the current files for your enjoyment!!!


Canonef.cpp Canonef.h main.cpp

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