Also to answer the original Question:
Just turn down the Color Saturation in you editing software all the Way, and you end up with a image that will only have brightnes Values, no color, basically black and white (Greyscale). If you then also want to make it look like some Black and white Film or an old B&W Movie, turn up the Contrast also. For more advanced Contrast adjustments use Color Curves. As NiNeff Allready said, there is no real reason to be able to do that in camera on the Chronos. For sure, most Smartphones and consumer Cameras would propably have the option for some B&W mode, but thats mostly just one of a bunch of fancy filters... Easiest way to do it on hardware (except you find an simple solution to make it work with the Color Matrix) would maybe be to get some HDMI Monitor or Recorder/Monitor which will allow for preview with LUTs applied. There are some, that can do this, but they are usualy not the cheapest. then just find a LUT or make on yourself, which makes your Color image into a Black and White one with the preferred Contrasts. The Camera will however still record in color and you would need to apply that same LUT later onto your files, but this would allow for a Real-Time Preview from the Camera in Black and White if this is something you need.