Solid state relay does not reset
The solid state relay you're using is designed for switching moderate current loads on and off, from a power supply, and not for switching signal lines. 

Unlike a mechanical relay, your solid state relay behaves as if there were a diode in series with the relay contacts.

You can likely easily adapt it to do what you want but you'll need to understand in which direction the current is flowing in your existing circuit. 

What's most likely is that the encoder signals to the camera by pulling the input to the camera low by connecting it to ground.

If that's the case you need to reverse the connections on pins 13 and 14. 

It's also possible that your camera has a very high impedance input, and that you need to pull the camera input low or high as appropriate with a resistor to compensate for the leakage current through the solid state relay.