Arsenal 2 does not officially support flash. However, some users have used a flash with Arsenal 2 in certain circumstances. The below will outline some of those limitations.
Using a flash unit with Arsenal 2
Arsenal 2 currently doesn't offer software support for flash triggering. You'll need to configure it from the camera.
If your flash has been enabled through the camera (see your camera's manual for instructions), it will be triggered when you take a shot using Arsenal 2 just like when you press the camera's shutter button.
Currently, only Arsenal 2's Manual Mode supports this approach. Arsenal 2's AI mode doesn't work with camera-controlled flash.
Using Arsenal 2 in your camera's hot shoe
The easiest way to attach Arsenal 2 to your camera is by placing it in the flash hot shoe. When installed this way, Arsenal 2 will prevent a built-in flash from popping up.
To access the built-in flash with Arsenal 2, simply remove Arsenal 2 from your hot shoe; you can mount it in other places (e.g. on your tripod).
Note: Mounting Arsenal 2 off-camera may reduce the effectiveness of Arsenal 2's vibration detection capabilities.