I decided to invest in a low light board video camera to see how much it could see at night;
It works on 12V and has a 1/2 inch CMOS sensor producing 800TVL (TV lines) and comes with two 3.5mm wide angle lenses. One with IR filter and one without. I used the one without and a small amount of digital zoom. Stated sensitivity is 0.00008 LUX. Size is near 1.5 inch (38mm) square.
For comparison this is what the Nikon could see about the same time:
Set it up looking through the kitchen window. Connected to the MacBook via a EzCap video capture device and saved some video every so often. With such a wide angle lens the bats look very small but the camera saw more activity than I did with the naked eye. Easier to see them with the video at full screen. As can be seen by the final clip it gets very noisy when the light level get too low.
I may be able to improve things. The camera comes with another board which has five push buttons. Once plugged in the main board it gives access to a menu to control video gain, contrast, etc.. There are various ghostly apparitions reflected in the window - me and an automatic light which detects movement in the kitchen.
Friday comes round again.
33 minutes ago