Soundy

Not exactly. CS refers only to the specific mount design (diameter, thread, etc.). CS mounts can have fixed-focal-length or varifocal lenses attached. Depth of field refers to the area, front-to-back in a view, that remains in-focus. It's affected by both aperture and focal length - a very short focal length will give you near-infinite DOF (meaning everything from very close, back to the far distance, will be in focus) but give a very wide view with little detail. Long lenses will get you a narrow field of view and give you more detail on distant objects, but the focus will become a lot trickier. There's some more info, along with some examples, here: http://www.cambridgeincolour.com/tutorials/depth-of-field.htm Nothing in the ad you linked to suggests that camera supports remote-controlled zoom OR autofocus. The wire you're referring to is likely the wire for the auto-iris drive, that allows the camera to adjust the lens iris in response to changing light conditions. The two small silver knobs you see on the bottom of the lens would be the zoom and focus adjustments. If what you looked at were mostly webcams, then yes, those would generally be limited to 180 degrees or less - they'd have little need to go beyond that. CCTV PTZ cameras almost exclusively have 360-degree rotation - as shoreview says, push to controller to one side, and the camera just goes around and around until you release the control. Just different styles. The dome provides protection for the camera mechanism, often as part of a sealed environmental housing. Dome PTZs tend to be more compact, because the camera itself is designed specifically to fit inside a dome. The "bubble" itself is usually a smoked plastic, so others can't see where the camera is pointing. The reason I asked if it mattered was mainly for cosmetics: if this camera was supposed to actually appear in your film, something like the Esprit would probably be more "telegenic", as people would be able to see it moving and aiming in different directions, thus reinforcing the image of it being a PTZ. In a typical dome PTZ, as described above, the camera itself isn't usually directly visible, so there would be no indication to viewers that the camera is looking around in different directions.

I prefer SSD/USB in a lockable slot. If failure, just take a shadow copy and send to customer by mail with the following instruction: 1. Unplugg power cord! 2. open Slot for USB stick. 3. Take out the USB stick and put the new one in. 4 Close the slot. 5. Plug in the power 6. Start up DVR. No need to send people put to fix it! Customer do themself! JD Friend of mine just went through something similar, in fact. He deals with the new LED sign boards on city buses, which are computer-driven, booting off 8GB CF card. He had a corrupted image on one, so he had the company in Britain upload a new image to my ftp server, and I put it on a DVD for him from there - he took that home and re-imaged a new flash card from their disc.

Will this camera be used strictly for providing video, or is a prop as well? In other words, does the "look" of the camera matter? In any case, most better "pro-quality" PTZs will do the trick. Pelco has some good models - Spectra if you want a dome (which needs to dangle from something), Esprit if you want something that can sit on top of a pole or platform. The Esprit includes a box housing similar to the EH3512, so a variety of cameras can be mounted inside it as well, giving more flexibility. If you want HD, there are IP-based megapixel PTZ cameras available as well, although those will generally have some slight latency that may or may not be a problem for you. As shoreview notes though, these will not be cheap (I think the Spectras and Esprits run in the $3000-$5000 range), but you really do get what you pay for in this business.

Amen to that (and not just entry-level - a lot of the big guys make it difficult if not impossible to find documentation online, too.

Ah, that makes sense, thanks! I've seen newer PC-based systems using SSD drives, as well as those with the OS and software on a Compact Flash card booting via either an IDE-to-CF adapter, or just a card reader on an internal USB header. Either method achieves the same end: your system is on nearly-indestructible (compared to standard HDDs at least) flash memory. It's actually something that could be done relatively easily with almost any PC-based system.

Not familiar with that term... it could refer to POS data capture, input- and/or output-relay support, something related to IP camera support... Can you provide any more detail? Type of clients asking for this (retail, etc.)? They provide any examples of systems that have what they're looking for? Any of these tenders describe what they want to accomplish?

That would be my guess, too... try cycling the power to the camera. I had an IQ753 that did something similar: the cut filter was getting stuck partway through its move, and simply rebooting the camera cleared it up (until next time). A sharp tap on the camera may loosen the filter up as well, which may or may not be a permanent fix.

How about four separate wireless baby monitor systems? Just take the little homogeneous monitors they come with and duct-tape them all together in a quad-display layout Sorry, just my morning silliness talking. How about WiFi cameras, a basic draft-N wireless router (11n for better range and speed, even if the cameras are 11g), and a simple NVR? I know WiFi cameras aren't generally cheap in and of themselves, but compared to finding the four-channel receiver you're looking for, it may be a most cost-effective option overall.

One thing to keep in mind with diodes and rectifiers: you WILL lose voltage across them. A typical silicon diode will drop about 0.7V; since a bridge rectifier basically inserts two of them in series, that will drop 1.4V or so. If you're using a regulated supply with a solid 12VDC output, you'll be lowering what the camera sees to barely 10.6V... even less with line losses. I'd test it with a single diode, first... if that doesn't help, going to a rectifier probably won't either.

I see it as more of a camera problem and would suggest it's best to avoid those where it occurs. Any decent modern camera should have isolated power and video to get the best balun performance in any case. Having to use an isolated supply because it's tied to the balanced twisted pair seems a bit of a kludge. It IS a kludge, but that's a drawback of CHEAP cameras. Save money in one place, spend it in another...

ISTR something about them wanting the theme ported to phpbb3 before putting it online. Personally, I think expedited access the benefits to the new version would far outweigh maintaining the exact look... there are lots of third-party themes out there and some should be very similar to at least keep the look "close". Nothing wrong with a facelift now and then anyway

How about this one? I have a good half-dozen or so of these sitting in my garage...

Why do I have this urge to hack Scorpion's profile and replace his avatar with a picture of a VCR??

I just installed another DVR (NDC was the brand, I think) with the same options. Near as I can tell, "FRAME" to them is the same as 4CIF - referring to the full size of the video frame. If I get a chance, I'll export a couple video clips at the two different settings to confirm.

The good thing is, if you had a 120VAC version, it would work fine with a step-down transformer (such as you might use to run any other North American device on European power). You might be able to just swap out the internal transformer for something appropriate as well (check the existing transformer's secondary voltage and current rating, then find a similar one with a 230V primary). BTW, koolmer, if you do end up having to use individual supplies, see if you can get "switching" types rather than transformers. They're FAR smaller and run a lot cooler, so it's easier and safer to pack them onto a single power bar. Cost may be the only issue, but most of the ones I see are no more expensive.

Yeah, I've run into it before... spent a lot of time puzzling over it, experimenting with it, asking around as to why it was happening with nobody really having a definitive answer or even a good guess... but coming from the audio world, I'm quite familiar with path-length ground loop problems. Best solution I know of, in this case, is to use 24VAC cameras. Since they naturally have an internal power rectifier, they don't share a common ground between the power and video, and thus don't have two ground paths. The other solution that SHOULD work (although I've not had a chance to test it) is if you have 12VDC cameras with internal regulators - again, something that effective separates the power and video grounds from each other inside the camera. Dual-voltage (12VDC/24VAC) cameras SHOULD also be free of the problem when used with 12VDC power supplies, for the same reason. However, I've found that even having a mix of cameras that include cheap 12VDC-only cameras can cause induced noise on other cameras. The problem is, once the noise gets into the ground plane of the system, it can get into any of the channels. Is this proven to work? Do they also sell in Europe for 230V? Essentially what this requires is the power supply to have an individual rectifier and regulator for each output channel - again, something that separates that channel's power ground from the others. You'd end up with something that's effectively one big transformer with a whole bunch of regulator boards inside a single box. "Individually fused" will have no effect on the problem. I had one other idea, that it might help to insert a diode in the power ground, ideally close to or inside the camera, to separate that connection somewhat... haven't had a chance to test that yet, either.

That would depend entirely on the TV. Most will default to whatever channel or input they were last on.

A ground loop of this type occurs when you have two different paths to ground of substantially differing length. Most cheap 12V cameras have a common ground for video and power, so right there you have two paths to ground, one via the power ground, and one via the video shield. Normally, using coax and power, or siamese cable, the two ground paths are essentially the same length, and there's no problem. If you look at the internals of a balun, however, they're effectively inserting a matching transformer inline with the two video wires, thus increasing the total length by the length of the wire in the coil windings, which could be dozens or hundreds of feet. So you end up with one ground path (on the power) that's maybe 30-100 feet long, and another (through *two* baluns) that's 10 times longer, or more. Within a single camera with an isolated power supply, this isn't usually a problem, but when you tie mutiple cameras into a single power supply with a common ground between all of them, and also have a common ground between all of the DVR's inputs, you end up with a mess indeed.

You can buy a simple adapter that will let you physically connect your camera to your TV's RF input, but as tomcctv points out, they are completely different types of signal. There are a few ways around this: if your TV has an A/V input (yellow, red and white RCA jacks), you can use the appropriate BNC-to-RCA adapter to connect the camera the the yellow video-in jack. Or if it has a SCART input, you can use the appropriate adapter for that. If the TV has *only* the RF (cable/antenna) input, you can use an RF modulator device to convert your video signal to RF (these are the same things often used to connect video games or DVD players to older TVs). Or, most older VCRs have RF outputs; you can use one as a video-to-RF converter as well.

Over 1.6km??? ashtech, there are a number of different options here... it really depends on what you're trying to do, what infrastructure you already have in place, and what you want to spend. For that distance, you could use fibre, or you could use an existing internet connection, or possibly active baluns.

Soundy could you possibly supply me with web references for the weatherproof connectors. I could give you dozens of links, but this is probably the easiest way: http://lmgtfy.com/?q=compression+bnc+connectors Hmm, GEM Electronics and ICM Corp. are two common ones that I use. Both make full lines of crimp-on and compression connectors, as well as baluns and other audio/video accessories. You will need different crimpers for these types of connectors, but if you're doing a lot of outside work, especially around the ocean, it's probably worth it to get into the weathertight connectors... plus, I find compression types generally a lot quicker and easier to work with - no loose center pins or crimp rings to mess with, they're a single piece and attach very solidly. ICM sells several nice kits that includes stripper, crimper, and an assortment of connectors, although I believe their crimpers will only work on their connectors... other manufacturers, like Paladin, make "universal" crimpers that can be adjusted to fit most connectors (I use this one, myself). You can jam grease into the crimps, or apply some to the wires before you crimp, but there are also crimps that are "pre-loaded" with a non-greasy gel intended for the same purpose: to keep air away from the connection and prevent corrosion and oxidation. We generally use this type (not an endorsement of this eBay seller, BTW, just an example of the connectors).

Interesting analogy The part Scorpion hasn't stated so clearly, is that H.264 requires substantial processing power compared to MPEG4... which either requires more powerful hardware, or a bunch of work-arounds to make the cheaper hardware handle it, which can create other problems. Indeed. When I asked about support for H.264 cameras (Arecont, specifically) on Vigil DVRs a few months back, one of Camacc's techs told me that their Aztech variation on MPEG4 could, in some instances, produce better compression with better quality than H.264, and that recompressing H.264 video with Aztech could even produce smaller files. I haven't tested these claims myself, but I trust the tech as someone who wasn't just trying to make me a sales pitch.

Hi soundy running sound/video/power/ ptz controls down coax is now very common. i realize that, but as i already said, 'There is no (cheap and easy) way to combine audio and video to run over a single wire', particularly in the context of this thread.

Not to muddle things, but for the sake of accuracy, you actually CAN run audio on coax... just not the SAME coax as the video. You can also run video on audio-type RCA wires, which as often as not are coax as well - those red and white RCA-tipped cables you normally see for audio are two thin coax wires.

Hi Soundy .. this sounded complicating to me .. what do you mean by "color artifacts in the B&W video" Briefly, when most DVRs display a B&W camera on a color channel, you'll see shifting color patterns on the image. This is a side-effect of color processing on greyscale vide, since greyscale video is still comprised of all three colors (red, green and blue), just all in equal amounts. With "lossy" video codecs (as with lossy image codecs, like JPEG), the image is examined and small variations in color are discarded - for example, an area with several very close shades of blue may be stored as just a single shade of blue, to save storage space. When you get shifting noise or lighting patterns in greyscale, that color processing can get "confused" and substitute full colors - say the brightness increases slightly between the time it processes the red and the blue components. Where the colors are actually balanced, the processor sees that there's more blue than red, so it will toss the red data and store the blue. When you view the compressed video, then, it shows that area as blue, rather than greyscale. You can see some examples in the gates at the top of this picture: The fix (or workaround, in some cases) is to zero the "Saturation" setting(s) for the B&W cameras. Some also have an option to simply tell the system that that camera is B&W or greyscale.