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GANZ LC-P36A/LCH-C36A CAMERAS

 

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In spite of all the advances made in image sensor technology, optics and digital processing in the past two decades the basic shape and layout of the standard video surveillance cameras has changed comparatively little. There have been exceptions and the range of specialist cameras has never been greater, but the fact remains that the traditional pattern, of separate camera module with screw-on lens remains the norm.

 

Clearly this arrangement has one important advantage; it gives the specifier or installer the freedom to choose the most suitable lens for the job. However, in the vast majority of cases the lens required is a relatively basic item. Around ten years ago Mitsubishi pioneered the concept of a combined camera and motorised zoom lens but despite initial enthusiasm it was a rather expensive and exotic solution, best suited to demanding situations.

 

Nevertheless, the idea was a good one and it has resurfaced in a somewhat simpler form. The fairly narrow range of lens requirements for routine surveillance applications appears to have been the starting point for the Ganz LC Series of cameras. The key feature is a fully integrated lens with variable focus and adjustable tele-wide setting, built into the camera body. LC series cameras are available in a variety of flavours, including colour and black and white models, with standard or high-resolution image sensors and with or without auto iris facilities. All models can be powered from a 12 VDC or 24 VAC supply; they tip the scales at 200 grams and measure 48 x 48 x 118mm.

   

The six cameras in the range use one of two types of lenses. The two we're looking at (LC-P36A colour standard resolution and LCH-C36A high-resolution black and white) have lenses with a focal length of 3.0 6-0mm and a maximum aperture ratio of 1:1.2. The iris range in both cases is F1.2 300 and the fields of view is: horizontal 72 36 degree (tele-wide) and vertical 52 to 26 degrees (tele-wide). The only significant difference between the two types of lenses lies in the iris range, which on the non auto-iris models is from F1.2 - 1.5. Resolution on the colour camera is stated at 350 lines with low light sensitivity of 1.5 lux whilst the black and white model is 570-lines and minimum illumination of 0.2 lux.

 

From the outside they do look quite different to a most other general-purpose CCTV cameras, almost as if the lens is missing. The controls for the focus and tele-wide adjustments are concealed behind a small removable panel on the left side of the camera body. They consist of two sliders mounted on the side of the lens assembly. Further along the left side there is a 8-way sub-miniature DIP switch, used to set the main operating parameters (more about that in a moment) and a deeply recessed trim pot for adjusting DC iris level. On the rear panel there is a single BNC socket for the video output, a simple two-way spring terminal for the power supply connections, a green power-on LED and an adjustment for line phase, when the camera is set to line-lock mode. On the underside of the case there is a mounting block with a standard threaded collar. This can be repositioned to the top of the case (it's held in place by two screws) to suit the mounting position or hardware.      

 

The front of the case the lens shroud is made from ABS plastic whilst the rear section, which houses the image sensor and control circuitry, is made up of two steel shells. Inside the case there is a simple chassis with the PCB boards stacked vertically along the length of the body, needless to say there are fewer boards inside the black and white model. The standard of construction is generally satisfactory however, this arrangement does mean there's quiet a bit of internal wiring, much more so that we've come to expect on this type of cameras recently. Whilst there's no suggestion that this will affect long term reliability or stability, the more electrical connections and electrical joints there are, the greater the opportunity for things to go wrong. The cases are not especially well protected against the ingress of dirt dust or moisture consequently they should only be used in relatively clean environments without further protection.

 

Set-up is straightforward. On the LCH-C36A (B&W model) the first two positions on the DIP switch are not used. Position 3 is for gamma correction (1.0 or 0.45), switch 4 controls edge enhancement (sharp & normal) and number 5 enables flickerless mode (1/100th sec fixed shutter). Position 6 is for backlight compensation, number 7 turns the auto electronic shutter on and off, and number 8 is for AGC. On the LC-P36A (colour) switch position 1 is for AGC, switches 2 and 3 are for setting white balance (fix/auto-trace and auto fix). Position 4 is for the shutter (auto/fixed at1/50th sec), number 5 is flickerless mode, 6 is for backlight compensation, 7 is edge enhancement and 8 is for line-lock or internal synchronisation mode. A small screwdriver is supplied for adjusting the DC iris level and line-lock phase trim pots. Lens adjustment can be quite tricky especially at the limits of the tele-wide setting -- since the length of travel for the levers is quite short.

 

PERFORMANCE

Actual resolution our two sample cameras was found to be a little below the manufacturers figures though part of the relatively small discrepancy could be attributed to the difficulty in accurately focusing the lens and the very touchy adjustment.

 

The LCH-C36A produced a well-balanced and detailed image with very little noise under normal scene illumination. The auto iris lends responds quickly to changing light levels and copes reasonably well with bright lights and areas within the scene. Low light sensitivity was as advertised and the image was very stable. All in all quite a good result.

 

The general performance of the LC-P36A was broadly in line with the manufacturer's claims though it proved to be less able at dealing with tricky or fast changing lighting conditions. It works best under strong even illumination, the auto-tracing white balance system has a fair stab at correcting for changes in lighting source and despite a fair amount of fiddling the picture usually ended up looking a bit too warm. Picture noise levels are very low in good light and once again the image is very stable.    

 

SUMMARY

Of the two cameras the black and white model turned in the most consistent set of results and it deserves to be considered as an alternative to a conventional camera and lens set-up, particularly if space is at a premium. The colour model works reasonably well in good conditions but it might not be your first choice for demanding applications, where there is a large variation in lighting levels or bright lights in the scene area. However, like its stable mate. It scores well on convenience, compact size and speed of installation.  

 

PRODUCT SPECIFICATION

 

Power supply              12VDC/24VAC

Weight                        200g

Dimensions                 48 x 48 x 118mm

 

PSI RATINGS

LC-P36A/LCH-C36A

 

Product                      

Product design 8/8      

Build quality               8/8

Ruggedness                8/8

 

Operation                  

General functions            8/8

CCTV functions            8/8      

Ease of use                 8/8

Instructions                8/8

Manuf. support                                   

Performance               8/8

Video quality              7/8

 

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R. Maybury 1999 1009

 


 

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