The bench test 2: The dark side of CCTV

What our experts say …

We are accustomed to seeing ruggedised video surveillance cameras designed for outdoor use and difficult conditions, but something about the EVS VNP-542 low light camera marks it out as different.

The substantial mounting bracket looks quite capable of supporting a camera many times the size and weight of this one. The use of a screw-on shielded multipole connector for the DC power supply and video output is unusual, possibly unique, on a camera of this type, and the cylindrical casing appears to be heavily armoured and obviously designed to withstand nuclear attack.

Everything starts to make sense once you know that EVS is a Russian company. It is based in St Petersburg and was founded in the early 1990s – at around the time of the collapse of the former Soviet Union – by employees of the All Union Scientific Research Institute of Television.

Clearly old habits die hard, and despite its small size, this camera looks and feels as though it was built to a state-commissioned, money-no-object military or industrial specification; all it needs is a coat of olive military drab... (EVS’s cameras’ initial applications included being used to capture images of the dark side of the moon!)

Needless to say none of this should be regarded as a criticism – quite the contrary. This compact monochrome camera’s formidable build quality can only be an asset in any extreme or harsh environment.

Moreover, the technology inside the case is reasonably up to date, with a 1/3-inch Sony Exwave HAD image sensor with 582 x 500 pixels, giving a claimed resolution of 380 lines and a low-light sensitivity of just 0.0015 lux.

St Petersburg can get a bit nippy in the winter, and this may have prompted the designers to ensure that the 542 isn’t going to get the shivers when the temperature drops.

A built-in heater fitted to the front window appears to be thermostatically controlled, but if so, it wasn’t working on our sample, which remained warm to the touch during our tests when the outside air temperature was getting on for 28 deg C.

The main camera body is basically a 65mm diameter cylinder. It’s just 55mm long, but there’s a 25mm extension piece attached to the rear panel, which holds the multipole DC/video connection socket.

On the underside of the cylinder is a solid metal bar, which bolts to the mounting bracket.

A simple plastic rain cover, bearing more than a passing resemblance to a short length of guttering, bolts to the side and rear of the camera.

All of the metalwork is vastly over-engineered, and everything, from the bolts to the steel mounting bracket, are twice as thick as they need to be. There’s also a liberal coating of mastic at any point where moisture and dust could get in.

Opening up the camera proved to be a bit of challenge. It’s a cunning design and the only way to get inside is to unscrew the front plate, but there’s nothing to get a grip of, so we had to construct a special three-pronged tool.

Aside from being highly vandal-resistant, the seal is hermetic and gives the electronic innards complete protection from the elements.

Inside there’s a single PCB board camera type module with integral lens. At first glance it looks a lot like an off-the-shelf product, but judging by the size and shape and the very average quality of the soldering, it could well be a proprietary design that’s built locally.

The same applies to the lens, though this time it’s an advantage. Whilst it looks like a typical plastic board camera lens, closer inspection reveals that it is a precision item, made of metal. The camera module is mounted on pillars bolted to the front cap.

Sandwiched between them, presumably to act as a heat shield, is a hefty slice of what looks like ‘Paxolin’, a material made from resin-impregnated paper, last seen in 1960s valve radios and TVs.

Setup and operation

The VNP-542 bucks the current trend for flexible power supply arrangements, and requires a 10 to 12.5 volt DC supply. Two types of mains adaptor are available – a standard model for indoor operation, and a heavy-duty model for outdoor use, which we assume to meet the requirements of the built-in heater.

There are no exterior controls or adjustments, but there is a two-way dip-switch and a couple of presets on the rear of the PCB, for adjusting auto iris level and gain. However, since the case is so tightly sealed, it is safe to assume that these are factory set and not meant to be tinkered with.

The non-standard supply/output socket on the back of the camera could pose problems for installers unfamiliar with this type of connector, though there is a simple wiring diagram on a label stuck on to the back of the camera. EVS can also provide a range of pre-terminated leads.

Mechanical installation couldn’t be easier. The wall bracket supplied with our sample is a model of simplicity and totally idiot-proof.

Performance

In brightly lit scenes the image tends to look a little washed out, especially when there is little contrast; it could be due to misalignment or more likely a consequence of the CCD’s very low light sensitivity.

Resolution is good, though, and it manages to capture fine detail without any problem. As we suspected, the lens is a quality item, and what’s more, the factory-set focus is spot on, which is just as well, as without our special tool and a lot of disassembly there’s no way of adjusting it.

The auto exposure systems handled rapid fluctuations in lighting levels with minimal lag or overshoot, but the graduations are a little coarser than usual and there’s no backlight compensation, so it may require careful alignment if there are any bright lights in the scene.

As expected, the VNP-542 really comes into its own in low light, continuing to provide a bright, clean image right down to near dark conditions. Noise levels increase steadily, but it remains well controlled until the last vestiges of an image have disappeared.

The CCD sensor on our sample had quite a few rogue pixels that started to glow up as the light levels fell, but again it wasn’t judged to be a problem in normal operation.

In spite of our misgivings concerning some surprisingly iffy looking soldered joints on the board camera module, the electronics appeared to be very stable and didn’t flinch when subjected to the customary battering form the Bench Test rubber mallet.

What the manufacturer says ...

EVS has designed and supplied cameras to the Russian military and government for many years. Our specialist low light cameras have the pedigree and testing of many years of military development behind them, and were originally designed to capture images from the dark side of the moon, for use with underwater submarine monitoring systems, and more recently to survey the downed Kirsk submarine.

Until recently such cameras have been at the very high end of the market, and have mainly been used by police and surveillance agencies, operating in ultra-low light levels down to 0.00004 lux.

Our cameras now offer this level of performance as standard, and equate to 2nd Generation Night Vision performance. We supply these ultra-low light cameras via Vaulted Image Technologies Limited in the UK and Ireland.

The VNP-542 camera can achieve an unprecedented level of sensitivity thanks to the use of CCD technology. This is attained by special processing of the video signal directly inside the CCD.

The simultaneous use of in-frame video signal processing in what we call ‘Night Mode 1’ in the camera allows us to increase the sensitivity by up to 1000 times (compared to standard CCD sensitivity), and get a record value for the camera based on CCD –0.00004 lux.

Because of the special modes of video signal processing employed, the sensitivity of the VNP-542 in night mode for both still and moving objects surpasses the sensitivity of other ‘special’ TV cameras by manufacturers such as Grundig and Panasonic.

The result is a camera that can be used on roadsides, in car parks, streets and commercial areas, without the need for expensive Infra Red Lighting. Also, the VNP-542 does not suffer from car headlights or moving objects producing the visual ‘smearing’ or blurred images typically associated with lower light operations.