To adjust the brightness on your MX-1, you will need to set the camera to Brightness Adjustment mode. 

While the camera is powered on, press and hold the LED toggle button for 4 seconds. 

The camera's power indicator will change to Purple when ready. You can use the Zoom In (+) and Zoom Out (-) buttons to raise or lower the brightness setting. 

To toggle off Brightness Adjustment mode, hold the LED toggle button again for 4 seconds.