How to add a sync port to a Canon 580EX

Since the Canon 580EX does not have a sync port, it cannot be used with some remote triggers, such as the popular and widely used Pocket Wizard Plus II. However, it is quite easy to add such a feature to your 580 by just mounting a 3.5 mm mono socket (a stereo socket also works but one terminal will be redundant). The operation only requires some basic tools and a minimum of soldering.
It should be mentioned that the space inside the speedlite is rather tight so use as small a socket as possible.

The first step is to switch off the strobe and remove the batteries.

Next, you remove the four screws at the bottom of the strobe (marked with red arrows).

Once the hotshoe foot is removed you can just pull out the five wire socket from the small PCB in the foot. The foot is now free from the strobe body and is much easier to handle. It appeared as if there was most room in the area marked by the red circle. The most appropriate position for the 3.5 mm socket is indicated with an arrow.

You only need to add two wires; one for the trigger pin and one for the ground. The easiest way is to first solder the wires to the 3.5 mm socket. All sockets look different, but the trig pin should be connected to the terminal in contact with the tip of the plug. In this case, it is the red wire. The ground should be connected to the terminal making contact with the inner part of the plug (black wire).

Now, it's time to drill the hole for the socket. In my case a 6 mm drill was needed. It might be easier to first drill a small guide hole. I used a 2 mm drill which maybe was a bit too small, but 3 mm should be fine.

Mount the 3.5 mm socket i the hole, without attaching anything else, to see if there is enough room in the strobe body.

If there is enough room, you just solder the wires as shown in the picture. Just in case I put some electrical tape on the socket if it would touch anything inside the strobe. If your mod doesn’t fit, try with a smaller socket or try to remove redundant parts on the socket to make it smaller.
Reattach the five pin socket and mount the hotshoe foot back on the strobe. 

Reattach the five pin socket and mount the hotshoe foot back on the strobe.
Connect your remote trigger to test the functionality and hopefully it works like a charm.
Happy shooting!