Security Installer

 BootLog.co.uk

HomeSoftwareArchiveTop TipsGlossaryOther Stuff

ERNITEC VARICAM

 

COPY

WHAT OUR EXPERTS SAY...

A truly universal camera that can tackle every type of application has to be the Holy Grail of video surveillance; it hasn't happened yet but it comes one step nearer with the Ernitec VariCam colour camera. The principle is simple; instead of mixing and matching separate cameras and lenses for different applications, one box does it all. It's not a new idea of course and Mitsubishi have been making fully self-contained cameras and lenses for several years (most notably the CCD-400 range). Many miniature board cameras also come with integrated lenses but the VariCam provides a greater degree of flexibility and convenience than has been previously available.

 

The key feature is the internal lens assembly. It has a motorised zoom with 10x magnification (focal length 5.8 to 58mm, aperture range f1.8/2.7) having a horizontal angle of view of 4.7 to 45.9 degrees. The exposure and white balance systems are both fully automatic. Zoom and focus can also be controlled remotely using a suitable telemetry system. Additional features include backlight compensation, switchable AGC; it has an external genlock connection and an S-Video output, which can be used at the same time as the composite video feed. The camera section is based around a 1/3-inch interline transfer CCD with a 752 x 582 (440k) pixel array. Stated horizontal resolution is 450-lines and low light sensitivity is claimed to be 2.5 lux and the signal to noise ratio (AGC off) is greater than 46dB.  

 

VariCam is housed inside a tough one-piece extruded alloy outer case measuring 54 x 62 x 117mm. A mounting plate (with a standard 1/4-inch thread) is attached to the housing with four screws; the plate can be moved to the top for an overhead or suspended mounting bracket. The internals are very well protected but the case isn't weatherproof and holes in the back panel and the top and bottom of the case provide an easy entry route in for atmospheric dust and contaminants. The front-end cap is dominated by a large lens that is surrounded by a protruding hood, which doubles up as a threaded mounting collar for adaptor lenses, but more about those in a moment.

 

There's much more to see on the rear panel. Along the top edge there is a row of four buttons; the two on the left side are for adjusting the zoom setting (tele/wide) and the two on the right are for manually setting focus (near/far). Below that there are four groups of rotary presets and switches. The first is for manually adjusting white balance. Next to that is the auto-iris level controls and in the middle of the panel is the electronic shutter set-up (1/50th sec to 1/30,000th sec continuously variable), plus a pair of miniature DIP switches for selecting manual or automatic focus and AGC. Video output is handled by a female BNC connector (composite) and mini DIN/Hosiden socket (S-Video). An 8-way spring terminal carries the connections for the power supply (12 volts DC), genlock input and remote control interface for external focus and zoom, using Ernitec BDR-51X series of telemetry receivers.  

 

Inside the case it is quite crowded with most of the space taken up by the lens housing and its servo motors. It is an off-the-shelf assembly very similar in construction and appearance to the ones developed for domestic camcorders. This arrangement means that the CCD sensor and its associated control/processing microchips are close to the rear of the unit. Above the lens is another PCB, also responsible for video processing and at the rear there's yet another circuit board for all of the input and output connections and set-up controls. Surface-mount components are used throughout which should help contribute to a long and healthy life. All of the components and boards are bolted to a very rigid steel sub-chassis; interconnections have been kept to an absolute minimum and the whole caboodle looks and feels very sturdy.

 

OPERATION

With only two connections to be made in most cases (DC power and video out), it doesn't take long to get the VariCam up and running. The focus and zoom controls make the business of lens selection effectively obsolete and simplify installation considerably, eliminating completely the need for any back-focus or auto-iris lens adjustment. Access to the manual adjustments and switches on the back panel could be better. It does depend on a set of miniature screwdrivers (they need to be in good condition too…), but provided enough room is left between the rear of the unit and any nearby walls it should go quite smoothly.  

 

The only adjustment that might slow things down is the setting of he auto iris levels. There are two rotary presets, one is for 'Area' level, and the other is labelled 'LVL', which stands for video level. The instruction manual simply points out that the area preset determines decides where on the image light levels are measured (all, centre or borders), and goes on to say that the video level control sets a higher or lower level… There's no specific advice on how to set it up, other than a list of the factory default values. The part covering setting the high-speed shutter is almost as brief though it does helpfully point out that shutter speed controls light sensitivity and it can be used to compensate for flicker from tube lighting. There are no technical details concerning the remote control options, other than to say it is compatible with the previously mentioned Ernitec telemetry receiver.

 

The zoom control is quite coarse and it can take a fair amount of button dabbing to get it exactly right. Manuals focus is smoother and much more progressive. We suspect the built-in zoom lens will cover 95% of routine applications but the VariCam can also handle awkward situations with the use of adaptor lenses. Currently two are available; a wide-angle converter lens that has a focal length of 4.6 to 46mm and a tele-converter with a 7.5 to 75.4mm range. The horizontal viewing angles for the two lenses are 6.9 to 55 degrees and 3.6 to 35.5 degrees respectively.

 

PERFORMANCE

Resolution checks and the results of our low light tests were very respectable and tally with the manufacturer's specs. In good natural light the image is crisp and packed with fine detail. Noise levels are about average for a camera of this type that is to say in a well-lit scene noise is negligible. As light levels fall colour disappears quite quickly and there is an increase in grain but it doesn't become intrusive until the picture is all but unusable. Image stability is excellent with almost insignificant levels of jitter.  

 

The auto focusing system is comparatively sedate with an occasional tendency to overshoot. It can also have difficulty in low light or scenes where there isn't much in the way of detail or strong contrast. It can also have problems shooting through glass and highly patterned objects can also cause confusion, however in most fixed camera situations it should only be necessary to set the zoom and focus once and leave it switched on manual operation. Auto iris operation is also fairly relaxed and it takes a few seconds for it to compensate for sudden changes in lighting level but in normal operation that shouldn't be a concern. On our sample colour accuracy in natural and tungsten light was on the button and the auto system is well able to cope with small variations. Under tube light we found it was necessary to set the white balance manually as the auto setting wandered slightly and in some circumstances -- notably mixed natural/tube light, could give the image a slight yellow caste.

 

Although not quite silent in operation the zoom and focus motors are very quiet and almost certainly inaudible above normal background noise levels, not that they're likely to be in action very often once the initial adjustments have been carried out.

Several sharp taps on the case and end panel confirmed that the electronics and internal connection are all rock solid and free of any intermittency.

 

OVERALL ASSESSMENT

It's difficult not to be impressed by the VariCam and as far as performance is concerned it compares well with most conventional camera-lens combinations in just about every respect. The only areas where it may not compete so effectively is in really difficult situations, where greater low light sensitivity is called for, or the lens requirement falls outside the VariCam's range, though such instances are likely to be few and far between. Clearly the greater cost of the motorised zoom and focusing systems, and the slightly higher risk of failure, has to be weighed against the price and reliability of fixed optics. However, we suspect the latter will not be a problem with this device as the build quality is of a very high order. In the end it is the simplicity of installation and flexibility that sets this camera apart from the crowd, it has the potential to greatly reduce the installers workload and it's ability to adapt to changing situations -- both short and long term -- is a key consideration. Of course none of this would matter one jot if on-screen performance wasn't up to the mark, but it is, and in some circumstances it works better than comparable fixed-operation models. Definitely worth considering.    

 

PRODUCT ASSESSMENT

Design and design features                      ****

Circuitry and components                ****

Ease of installation and wiring            ****

Range and variety of functions            ****

Accompanying instructions              ***                            

Technical advice and backup            ****     

Value for money                         ?                          

 

---end---

Ó R. Maybury 1999 0401

 


 

[Home][Software][Archive][Top Tips][Glossary][Other Stuff]


Copyright (c) 2005 Rick Maybury Ltd.

admin@rickmaybury.com