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APPRO TECHNOLOGY BV7105
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WHAT OUR EXPERTS SAY...
First impressions are really important and the BV7105
monochrome camera gets off to a very good start. It looks and feels like a
tough little customer. In addition to being very compact -- it measures just 52
x 42 x 84mm without a lens -- it is light and easy to fit, tipping the scales
at just 220 grams.
The BV7105 is part of the Appro 7100 range, marketed in
Britain and Eire by Robot UK. This particular model requires a 24-volt AC or DC
supply; the range includes a 12 VDC version (BV-7105S) and a 24VAC model (BC-7108)
with external line-lock facility. All three are built around a 1/3-inch
interline transfer CCD image sensor, the BV7105 and 7105S have a quoted minimum
low-light sensitivity of 0.05 lux. The BV7108 (line lock model) has a low light
sensitivity of 0.2 lux plus an additional backlight compensation mode. The
manufacturers claim a resolution of 420 lines on all three models, with a signal
to noise ratio of 42dB, all of which marks it out as a reasonably well-specified
mid-market camera.
Build quality is very good; the two-part case is made of steel,
with cast alloy end caps. The camera will work with a wide range of lenses; the
mounting collar is designed for CS types, C mount lenses can also be used with
a suitable adaptor ring. The back focus adjustment is carried out by slackening
off a pair of tiny grub screws set into the mounting collar. Next to the lens mount
there's a red LED power on indicator.
The back panel is dominated by a single BNC socket carrying
the video output, and a 6-way screw terminal. The first two terminals are for the
power supply connections, terminals 4 to 6 are set aside for an auto-iris lens.
The camera can be used with video or DC controlled AI lenses, selection is
controlled by a three-way miniature DIP switch. This also switches between auto
and CCD iris and gamma correction (0.45 for indoor use or 0.65 for natural
light). The only other control accessible from the outside is an ALC preset --
located on the right side of the camera body -- used for setting DC control
auto iris lenses.
The bottom part of the case forms a simple chassis. Inside there
are two fibreglass PCBs. A board camera module -- mostly populated with Sony
chips -- is fixed to the front end cap.
The second PCB, which is bolted to the bottom of the case, contains the power
supply components, AI control circuitry, sockets and switches. Both boards use
mainly surface-mount components. The internal wiring, such as it is, is of a
very high standard and the whole assembly looks as though it will be able to withstand
a fair amount of rough treatment. Nevertheless, the case is not very well
protected against the elements; as it stands it is designed for indoor use in a
non-hostile environment (-10 to +50 degrees centigrade). Dust and moisture will
be able to find their way inside through gaps in the case, around the DIP
switch, terminal block and ALC preset hole. Standard 1/4-inch UNC mounting
threads are fitted to the top and bottom panels.
OPERATION
The instructions -- such as they are -- occupy two sides of
an A4 sheet of paper. It contains all of the information an experienced installer
is likely to need, though it might have been helpful to include a little more --
indeed anything -- on lens compatibility and selection or some advice on
location and ALC adjustment.
To be fair, with so few controls or set-ups to worry about
installers shouldn't encounter too many problems with this device. The only thing
that might slow down the proceedings is the back-focus adjustment. The grub
screws are very small indeed and might be awkward to locate when the camera is
in position.
Although the camera body is quite small bear in mind the output
cable will add a couple of centimetres to the rearward clearance. We suspect
that some installers and end-users would appreciate a means of disabling the front
panel power-on LED. As far we can see the only way to do it is to dismantle the
camera and physically disconnect the power feed, or tape over the LED.
PERFORMANCE
The camera's low light sensitivity is as advertised and it
will produce a useable -- albeit rather grainy -- image in very poorly lit
conditions. The horizontal resolution on our test sample was within a whisker
of the spec at just over 400-lines. In good light the image is very clean
indeed, picture noise levels are below average for what amounts to a
budget-priced camera. With gamma correction set to 0.45 the contrast range is
very good indeed (even on strongly lit outdoor scenes), though it's worth
experimenting with the alternate setting, especially if the scene contains a
lot of white or reflective surfaces.
The auto exposure system responds quickly to general changes
in scene illumination though it does tend to over-compensate for bright lights within
the scene area. If that's likely to be a problem it may be worth checking out
the 7108 which has an additional backlight compensation control.
OVERALL ASSESSMENT
In spite of its small size and low price the BV-7105 is a
very competent little camera, with the kind of low light performance normally
associated with more specialist designs. The relative simplicity means it can
be installed quickly and easily, and in most cases the set up will take only a
few moments. It is sturdily built and judging by the quality of the internal
circuitry it should enjoy a long and healthy life.
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 ****
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R. Maybury 1998 0709
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