Two more that might help you -
Focal Length Calculator
Calculate the focal point of a camera to help determine the best size lens to order. Save & view your results later.
ipcamtalk.com
IPVM Camera Calculator
Using Google Maps, layout and design cameras, choosing from 10,000+ models, delivering FoV and image quality previews plus export to PDF, Powerpoint and more
calculator.ipvm.com
Above all, don't get caught in the megapixel trap. It takes the right sensor size to produce a good night video at each specific resolution -
Disclaimer - These sizes are what the manufacturers advertise and may, or may not, be the true size of the sensor in the camera.
1/3" = .333" Great for 720P
1/2.8" = .357" (think a .38 caliber bullet) Great for 2MP
1/1.8" = .555" (bigger than a .50 caliber bullet or ball) Great for 4MP
1/1.2" = .833" (bigger than a 20mm chain gun round) Great for 8MP