Lacking a "two-position" button (such as the built-in shutter release of the ZX-series cameras) I used two momentary-contact normally-open buttons. One button is used to activate the meter of the ZX-M (and the auto-focus other ZX-series cameras) and the other is used to release the shutter.

The socket on the camera body has three pins, and the spacing of these pins is the same as industry-standard circuit-board headers. I used a three-hole connector salvaged from old computer case.

Wire the buttons such that one connects the two outer pins together when the button is pressed and the other one connects the center and upper pins together when the button is pressed. The former button will activate autofocus and metering. The latter button will release the shutter.

In use, the first button is pressed to take a meter reading, and then released. The second button is then pressed to release the shutter. Care should be taken as the shutter can be released without first taking a meter reading or activating auto-focus.