On Tue, Aug 1, 2017 at 2:59 PM, David Niklas doark@mail.com wrote:

I don't know how long a reasonable MIPI-CSI cable can be

I have some experience with this. We were able to do over 1 meter via an HDMI cable and some adapter boards. The actual distance will depend on a few things. Ideally you want to run the wires as twisted differential pairs, ideally shielded at one end. A ribbon cable isn't perfect but may work. Even if it works, you may be spewing EMI around like crazy. Anecdotally, that happened to the Raspberry Pi Foundation, their MIPI-CSI cable for their camera could only be 50mm or so long; any longer and they wouldn't have been able to pass whatever EMI tests they had to pass.

My other problem is that I don't know what the f-number aught to be. My original idea for using the camera is this:

That completely depends on the size of the sensor, and what you want in the field of view. If you have room for a camera with an M12 lens mount, you can buy a few different focal lengths for cheap and swap them out as you'd like, until you find something that works. If it does not have an M12 lens mount, then you're stuck with whatever choices they have. If you're buying a lens-and-sensor module, then they'll give you the field of view in degrees; in this case, don't even worry about the focal length. The FOV is probably what you're after anyhow, and they should give you this.