What our experts say …
It came as something of a surprise to learn that the TK-C686WPE is JVC’s first IP66 rated PTZ dome camera with an outdoor housing. The company has been in the surveillance business for so long that we naturally assumed that even if there wasn’t one in its current range it must have had one or more of them at some point in the past, but no, apparently this is it. But from the looks of it they’ve hit the ground running.
Of course JVC are no strangers to PTZ domes, and the differences between cameras designed for indoor use and models booted and suited for a life in the great outdoors are often not that great, but even a cursory glance at this one suggest that the C686 is more than just a simple repackaging job.
Nevertheless, the exterior styling is fairly conventional, and JVC hasn’t strayed too far from the well-beaten track, but look closer at the housing and you may notice that it is a tad more streamlined than usual. This should contribute to stability in high winds, which, as we shall see in a moment, is an important consideration on this particular model. However, the most unusual external feature is the transparent dome, which is more prominent than most of its rivals. This gives the camera a slightly wider vertical rotational range, from -5 to 185 degrees; every little helps, as they say….
The camera is a high performance day/night design, built around a 1/4-inch interline CCD with a 410k pixel sensor array. JVC claim resolution is 540 lines and it has a low light sensitivity of 0.04 lux, in night mode with all of the various AGC and processing options engaged. The camera is coupled to a powerful 36x optical zoom lens with a switchable IR cut filter, which moves out of the way when it is in black and white Night mode. There’s also a digital zoom presettable from 2x to 32x in five steps.
Other highlights include a privacy mask function, image stabiliser and a motion detector with tracking function that follows a moving subject or object from the Home position. But the real star of the show is the pan and tilt mechanism, which is a significant departure from the usual arrangements of gears, belts and pulleys.
JVC has taken what might be seen as a bold step and used a direct drive motor system for the pan and tilt mechanism. The key advantages are speed and accuracy. JVC also points out in its publicity blurb that it is almost completely silent, though it’s hard to see how this is a benefit when the dome is quipped with two fairly noisy fans….
Nevertheless it is fast – very fast, in fact. Pan and tilt speeds of up to 500 degrees per second are possible when the camera is moving between preset positions (up to 100 can be stored). Positional accuracy is in the order of 0.01 degrees. The camera platform’s agility isn’t at the expense of precision and under manual control it can move at a barely perceptible speed of 0.04 deg/sec.
You have to ask: if direct drive is such a good idea, why isn’t everyone doing it? It’s not exactly a new idea but it has posed some formidable challenges that JVC appear to have overcome.
The lack of gearing reduces the amount of torque the motor can deliver. This means that the moving parts have to be a light as possible and in this case the camera and pan platform are mounted on ultra-low friction bearings. In fact the mechanism moves so freely and is so finely balanced that with the power off the camera will move if you blow on it hard enough. When the dome is powered up the camera module and platform tightens up considerably, but without the friction of gears and pulleys it is more susceptible to movement and vibration; however, provided the mount is sufficiently solid, it really shouldn’t be a problem.
Rigidity and effective weatherproofing are vital in order to protect the delicate components, so the mounting bracket and the dome housing are all a little sturdier than usual and made from precision alloy castings, encased in a lightweight plastic shroud.
Maintaining a consistent internal temperature is obviously very important as well, to keep those precision bearings running smoothly. To warm it up there’s a substantial fan-assisted heating element that takes up almost three quarters of the inside edge of the housing, and to cool things down there’s a second much smaller fan embedded in the camera module’s mounting bracket.
The clear dome and its rubber sealed mounting collar are held in place with four screws and attached to the dome by an anti-drop cable. The housing also has a small panel containing a switch for the heater and three sets of DIP switches; two are used for setting protocol, sync, terminations and dome ID; the third one appears to be unused. Power (24 volts AC) video output, comms and alarm cables emerge through the back of the mounting bracket.
The PTZ camera module sits in the middle and is held in place by a pair of quick-release latches and protected from gravity and butter-fingered installers by a second anti-drop wire. A multi-way connector on the top of the module links it to the electronics in the top of the housing and installing or replacing a PTZ module should only take a few moments.
The module is built on a cylindrical cast alloy chassis with the camera and its associated circuitry fully enclosed in an almost spherical metal case. Beneath it is a single PCB that handles most of the dome’s other functions. Build quality is generally excellent and with so few moving parts there should be very little to go wrong.
The only small area of concern for us was the ribbon cable that connects the camera module to the platform. This twists to an alarming extent as the camera rotates. We are sure this has been taken into account and must have been extensively tested; it’s not listed as a consumable part. Even so, it does strike us as being vulnerable to fatigue.
Setup and operation
Access to our review camera’s setup menus was via a matching JVC RM-P2580 control unit. The camera main menu has eight options, starting with Camera Function 1, which covers setting vertical phase, camera title/ID position, sub menus for setting up the Privacy Mask and Tracking Motion Detector and enabling the electronic stabiliser (three levels). Camera Function Menu 2 is concerned with the Auto Flip function, for tracking a moving subject as it passes beneath the dome, enabling variable pan/tilt speed when zooming, ‘Easy’ auto focus setup, auto focus sensitivity adjustment for B&W/Night mode, setting Pan and Tilt limits and selecting Auto Return mode (Home, Auto Pan, Auto Patrol) and time delay.
The Camera Title/Alarm menu does pretty much what it says and is used to set a camera title, select and set display ‘Areas’. Set alarm title, size and colour, select alarm inputs and outputs.
Camera ALC deals with setting manual shutter speed (1/50 to 1/1000th sec in 8 steps), AGC mode (mid, high or super), Sensitivity Up (x2 to x128 in 7 steps), ALC mode, Day/Night Mode adjustment (B&W, Colour, Auto, level, time delay and light type).
On the Camera Video screen there are options to set monitor type (CRT or LCD) DVR save mode, colour level, enhance level, Pedestal level, DNR mode and SEC mode (emphasises fine detail). The Auto Pan/Patrol/Trace menu is also self-explanatory and is responsible for setting up automated camera movement patterns with options to program exposure presets (iris mode, backlight control, and white balance).
A similar selection of camera settings is available on the Position Function Set menu and this also includes an option to create a title for each position of up to 16 characters. And finally, the Factory Settings menu returns the camera to its defaults, with the option to retain Position data settings and titles. Although the menus cover a very wide range of functions, in typical JVC fashion the on-screen displays are clear and easy to follow and none of it is particularly taxing, just time-consuming if you are going to take advantage of all of the facilities on offer.
Performance
Although our memory may be slightly hazy on past JVC PTZ domes we can say with some certainty that the image produced by the C686 is as good as anything we’ve seen before from the company, and better than many rival products. In good daylight the image is sharp and bright and packed with lots of fine detail, resolution is at or near the figure on the specs sheet and colour accuracy is spot on.
Noise is only apparent at very low illumination levels and night mode engages well before it becomes intrusive. Low light performance is also impressive and provided there’s at least some available incidental light it will generally produce a useable image. The auto focus system had a tendency to hunt, especially at higher magnification levels, but this is to be expected and switching to manual control is not a problem.
Some internal reflections are produced by the dome, especially when there’s a strong light source nearby striking the cover at right angles, but we have seen much worse.
Under automatic control the camera moves at lightning speed between positions but it’s silky smooth and as docile as a lamb when driven from the joystick, with virtually no overshoot on a very fast pan or tilt.
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