Bactrim

Over last weekend, I started working on EF-NX AF adapter. I am not sure if I can do this and how long it will take to complete.

Anyway, I began to research EF mount and its protocol.

I found a web site which contains good enough EF mount protocol info. to start.

https://pickandplace.wordpress.com/2011/10/05/canon-ef-s-protocol-and-electronic-follow-focus/

The basic pin-out as below.

EF-PinOut

You can see detail info about the pins in the above link.

Motor power is 6V, and Logic power is 5.5V. Logic communication uses SPI protocol. Camera body is a master and lens is a slave.

In order to try to control a EF lens, I needed to reverse-engineer to get mount/pins dimensions.

Below screen shot is from my CAD screen after getting initial dimensions.

 

 

EF-Mount

For controlling a EF lens, I used Arduino to understand the protocol. I 3D-printed for contacts holder and made contact extension cable for the test.

I took video clip for a EF lens control. It shows moving focus from MIN to MAX position and back and forth the focus position with rotary encoder.