As has been mentioned, at that height you'll never get anything meaningful enough to make an ID of who is doing what.
Start reading the
Wiki, in the blue bar at the top of the page. A few basic pointers in the mean time -
The smaller the lux number the better the low light performance. 0.002 is better than 0.02
The smaller the "F" of the lens the better the low light performance. F1.4 is better than F1.8
The larger the sensor the better the low light performance. 1/1.8" is better (bigger) than 1/2.7"
The higher the megapixels for the same size sensor the worse the low light performance. A 4MP camera with a 1/1.8" sensor will perform better than a 8MP camera with that same 1/1.8" sensor.
Don't believe all the marketing hype no matter who makes the camera. Don't believe those nice night time captures they all use. Look for videos, with motion, to determine low light performance. Rule of thumb, the shutter speed needs to be at 1/60 or higher to get night video without blurring.
Read the reviews here, most include both still shots and video.
The 5442 series of cameras by Dahua is the current "king of the hill". They are 4MP and capable of color with some ambient light at night. The 2231 series is a less expensive alternative in 2MP and does not have audio capabilities, no built in microphone, but is easier on the budget. The 3241T-ZAS has similar specs as the 2231 and has audio. There are also cameras available from the
IPCT Store right here on the forum and from Nelly's Security who has a thread in the vendors section.