[DIY] EF-NX AF Adapter - EF Lens Control Test

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.

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.

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.

https://www.youtube.com/watch?v=7fM5RKraDdA

great to see that you "accepted my challenge":

http://www.dpreview.com/forums/post/57301534

Please keep us posted. You are great, btw.

Just a thought, Kickstarter?

I would be one of the first supporters if the price was reasonable.

tecnoworld wrote:

great to see that you "accepted my challenge":

http://www.dpreview.com/forums/post/57301534

Please keep us posted. You are great, btw.

I just merely saw a rabbit in a hole, but I have no idea how the hole is deep and long. I am going down, but not sure I can catch the rabbit or am stuck in the middle of hole with bare hands.

We will see.

ILHYOUNG.

ocphotodad wrote:

Just a thought, Kickstarter?

I would be one of the first supporters if the price was reasonable.

I haven't done it before, and I guess it is too early to tell about it.

ILHYOUNG.

I looked at doing this once I realized that both use spi (unlike Nikon) and that voltages are not exotic. I tried reading your excellent site with Google translate but... Then I realized that I actually don't have any decent canon glass and that I'm more of a software guy anyway

I think even enabling ois and aperture control (which I think could even work independently of camera) would be great - AF of any kind would be fantastic for people looking for long lenses (and ultra wide ones).

TLDR Great work, best of luck!

otto k wrote:

I looked at doing this once I realized that both use spi (unlike Nikon) and that voltages are not exotic. I tried reading your excellent site with Google translate but... Then I realized that I actually don't have any decent canon glass and that I'm more of a software guy anyway

I think even enabling ois and aperture control (which I think could even work independently of camera) would be great - AF of any kind would be fantastic for people looking for long lenses (and ultra wide ones).

TLDR Great work, best of luck!

Thank you for your kind comments.

I am a SW guy, too. I learned CAD and EE by myself. So, almost everything is new to me.

As you mentioned, Canon EF mount SPI uses 5 or 5.5V and NX uses 3.3V. I need to convert this 2 voltages when it talks to EF lens.

I found below product to do its work.

https://www.sparkfun.com/products/12009

We will see how that will work.

BTW, your findings for NX500 shell script are amazing!!! Please keep up!!

ILHYOUNG.

Nx1 and nx500 are probably better than anything apsc canon will produce in the next 2-3 years, at least.

May I suggest that at least initially you could use external power for lens? IIRC some (Nikon though) lenses can draw a lot of power and there is a real risk of overloading nx side. 5x1.2V NiMH would do for 6V and a diode would decrease it to ~5.5V. You could then measure the current used by the lens and compare it to current provided for native NX lens.

cookedraw wrote:

don't do it, it will only push up the prices on second hand market when the canon people wake up.

Just kidding, do what you want man, nice to see people hack NX-system.

Thank you. It will be an interesting try.

noflashplease wrote:

The problem with that statement is that Canon is still in the camera business. In 2 or 3 years, will you still be able to get a NX1 or NX500 repaired. Canon supports cameras for up to 10 years. In 10 years, how many of the last Samsung NX bodies will still be operable and in use?

The greatest advantage of a short flange mirrorless body is that with an adapter you can use it to bring life to a lens from a dead system. To give an example, Contax G and N mount lenses can be mounted and autofocused on Sony A7 bodies with an adapter.

I am a NX1 owner and I agree a good number of people want to use EF lens on their NX body. So, I decided to work on EF-NX adapter.

At this moment, I am not interested in E-mount system.

As you mentioned, E-mount system might have a bright future. So more chance might be that someone who is interested in both NX and E-mount will work on the adapter.

ILHYOUNG.

ocphotodad wrote:

Just a thought, Kickstarter?

I would be one of the first supporters if the price was reasonable.

Yes, I'd sign up for kickstarter, if you get it working.

I'm in for the kickstarter!