Night Vision vs. Day/Night CCTV Cameras
True day/night CCTV cameras have imaging sensors that can register both IR and visible light. During the day, the IR component of the spectrum is eliminated using an IR cut filter.
This enables them to compensate not only for low ambient light conditions, but also for variable ambient light. In other words, their firmware can adjust the image so that you get a clear picture both during the day and during the night.
Day/night CCTV cameras are particularly useful for monitoring locations that need 24/7 surveillance, since they can provide clear footage throughout the day.
Camera Range
A variety of optical parameters – at the most basic level, the focal length – determine the range that a CCTV camera can cover. The rule of thumb about it is simple: a higher focal length means a camera can focus on objects that are further away, but it also means it covers a narrower area. In other words, it can cover a greater distance, but its field of vision is narrower.
Many night vision security cameras will explicitly list the maximum distance they can cover. This is particularly relevant for day/night CCTV cameras, because the maximum distance that they can cover is not determined only by their optical parameters, but also by the intensity of their IR light and the sensitivity of their imaging sensors.
Image Quality
When talking about a CCTV camera’s image quality, we tend to lump together several factors, such as resolution and sharpness. Some of these parameters are correlated, but in surprising ways!
Image resolution is the most obvious aspect. The higher a camera’s resolution is, the more details it can capture in a well-focused image.
1080p (2 MP) cameras are generally sufficient for most scenarios, but higher-resolution cameras – 4K or higher – may be useful if you need detailed surveillance over a wider area or at high distances. However, it’s worth remembering that a higher image resolution also results in higher storage requirements!
How sharp an image is depends not only on the camera’s resolution, though, The minimum and maximum distance at which a camera can provide a sharp, focused image depends on a variety of optical parameters, in addition to the sheer quality of the lens(es) and imaging sensors. Consequently, you want to pay attention to optical specifications as well as resolution.
Power and Connectivity
We are so used to seeing CCTV cameras everywhere that we tend to think of them as these tiny electronic islands of sorts, but in truth, they aren’t. Like all electronic devices, they need electrical power to work – and they need to transmit their pictures somehow. In fact, this is their giveaway. If you were wondering how to spot night vision cameras, this is it. Look for the power source.
Most CCTV cameras today are IP cameras, which means they plug into a computer network. Unsurprisingly, then, night vision CCTV cameras come in wired or wireless options.
Wired connections are cheap and high-capacity, which means that they are particularly useful for cameras that need to send high-resolution pictures or cameras that need to be very cheap. On the other hand, you have to run a data cable to them. That means extra maintenance and installation effort, not to mention a cable that an intruder can simply cut if it’s exposed.
Wireless CCTV cameras do away with the data cable, which makes them convenient to install and operate. However, their range is limited to the access point’s range. Nowadays, Wifi networks are fast enough that you can stream high-resolution images over a quality connection – which is to say that wireless cameras are not a good option in areas where you can’t rely on a strong Wi-Fi signal.
Many Wi-Fi cameras are battery-powered, so that they are, indeed, truly cable-free. At the other end of the spectrum, many wired cameras use a technology called Power over Ethernet (PoE), which enables them to use the same cable for both power and data connectivity.
Connectivity doesn’t directly influence a CCTV camera’s night vision capabilities, but it does influence deployment options, which can be relevant for nigh-time surveillance. For example, wireless cameras are easier to deploy along fences than their wired counterparts.
