Cameras can not see in total darkness. You will need IR illuminators either built around the camera lens or as a separate lighting source (only for a B/W camera or a D/N camera). We do carry cameras that works in very low light conditions. Lower the lux rating, better it is under low light.
Do your cameras work with different voltage for other countries?
Most of our cameras come with a power adapter that can handle form 110V ~240V AC. In case you get a camera with direct AC plug-in such as clock radio camera we will include the 220V to 110V (60Hz) step-down converter. However, if your country uses 50Hz, the time on the clock, because it is digital, will not be correct (it will be off about 20 min a day)
How far or how much can you see with a camera?
Cameras can see Infinite, therefore It all depends on the size of the object. Wider the angle of the lens, smaller it will appear but area coverage will be greater. You can not have both zoomed in view and cover wide area. Most of our cameras come standard with wide angle lens (75 deg horiz) that will cover the whole room if placed at the corner looking towards the center of the room. Try our CCD Lens Calculator for more information.