I need to add IP cameras to my 'warehouse' area. What do I need to look for as far as camera specifications go. I need some that have good resolution then I can use some that do not have to be that great. The good resolution ones will have cover an area of about 8' x 8' x 6'. The not so great ones will cover a much larger area - total will be 50' x 100' x 12'. I assume the price goes up with the resolution.