phred

Could you please explain 'double encoding' Do you mean variable bit rate encoding? What codec are you using?

OSC 9600 series see them at www dot dvr.com IL DVR Vangold - Shenzhen Vangold Electronics

It's a Botch Minion I C O more useful as a door knob. Less useful than a man's tits.

Tolerances for chip design are so stringent that a production run of the same CCDs will give a range of qualities. Similar thing happens with CPUs, some will get hotter than others when tested so are given a different speed rating.

When control function is done by software it becomes potentially unlimited.

Time to get a posse up, I'll bring my claymore and cut the runts legs off. Makes my blood boil.

See what you mean, that would be more convenient. Ken may have a point about advertising but you obviously have plenty of opportunity to see what is on offer. Perhaps you deserve the special privilege, considering the contribution you have made here, I can't think why anyone would object.

Light from the sun contains much IR but the visible light causes the eye to close down, protecting the retina. The eye does not respond to IR so stays wide open if you are in the dark, your retina takes the full blast. Even powerful illuminators may do little damage if you are a short distance away but close in you are getting the full force. Damage to eyes by IR was a common problem in foundries and is well documented. Keep wearing the shades

The little laser pointer works very well at night and allows aiming of the IR without it being on. I do not like getting too close to these illuminators in the dark, intense IR can damage your eyesight.

atropine What an appropriate name for a question on irises. Auto iris is usually essential for outdoors of where light levels vary considerably. Current CCDs have a limited dynamic range, an iris effectively increases the range. The old Vidicon tube cameras actually had an extremely wide dynamic range so a manual iris was fine.

Have you got the 'Always notify me of replies' box ticked in your profile?

Minimum Lux level is a camera CCD sensitivity rating. The lower the Lux figure the better for low light. Rough guide: Street lights 1 – 10 Lux full moonlight 0.1 Lux dark cloudy night 0.0001 Lux So in theory anything lower than 0.1 Lux should do if there is some lighting nearby. Unfortunately, manufacturers specs are not exactly reliable. Many use tricks like frame integration where the camera 'holds' several frames and adds them together to enhance apparent low light performance. This effectively reduces the shutter speed and motion will appear blurred. The big brand names tend to have more honest specs, so a Panasonic rated at .1 Lux may outperform a no-name that uses frame integration to obtain a rating of .001 Lux

2X teleconverters, also known as range extenders, effectively double the focal length of the lens, so an 8mm becomes 16mm. As you might expect, there is a tradeoff. With a converter fitted you are effectively only using the central portion of the lens, so the amount of light that reaches the CCD is reduced - a 2X converter will cost you 2F stops. For the same reason the effective l/mm resolution is also reduced. They are only worthwhile if they are good quality and fitted to a top quality lens. I would limit their use to low TVL Cameras.

Chateau's 4 channel will do 100fps D1 8 channel with similar spec is the same price. Less than a third of the price of the NV7000H in the UK

'Abhorration' may not be the correct spelling but is certainly a more appropriate description for the abhorrent mess that spherical lenses can make of an image. Aspherical lenses do tend to perform better in almost every respect. They first appeared in the 17th century - seems to have taken a while for cctv to catch on.

Intense Ifra Red can damage the retina of the eye. How much it takes to damage a baby's eyes is undocumented. Much safer to use low level conventional light. You may wonder how this can be, when sunlight contains so much infra red. Sunlight contains visible light that causes the iris of the eye to close. The eye does not respond to infra red, so in darkness, under infra red light, the iris will stay full open and the retina will get the full whack. You will get better results for the money if you stick with black and white cameras.

NV7000 uses older MPEG4 hardware encoder. The NV7000H is the one that will do H.264 8 channels and total 50fps at D1 PAL Extraordinarily expensive in the UK

Videobruce To answer your question about a 480 TVL camera I have looked at the detailed spec on a Sony 480TVL CCD (ICX084). In order to ensure the lens is not the limiting factor in overall resolution, you would need a lens capable of 50 l/mm. Despite being a rather modest spec many cctv lenses will not reach this resolution. This is why you need special lenses to get the best from megapixel cameras, unless they use much larger sensors.

Don't have a list but here is one to add. Chateau Technical Corp. Taipei, Taiwan. Their cards run true H.264 on TI DaVinci chips. The best I have seen so far ( I don't sell them btw) Also see this thread http://www.cctvforum.com/about8126.html The Chateau Tech cards have much better software and give similar quality video but with a tenth of the file size.

Thats why we have so many cctv cameras ... something more interesting to watch

You're being very generous. The maximum recording resolution and frame rate are fundamental DVR specs. This is really basic stuff, anyone who does not know what these figures mean should not be selling DVRs, they are in no position to give good advice.

Sounds similar to the 21 megapixel SentryScope camera. Some nice sample images here http://www.envisagetechnology.com/SentryImages.html (right click -save target as) load them in XP picture viewer and zoom in. Also heard they are working on an 84 megapixel version.

There is no mathematical correlation between pixels and TVL. It is largely a subjective judgement. As a rough guide To convert horizontal lines of resolution to pixels, multiply by the aspect ratio and divide by the Extended Kell factor (usually taken as 0.7) Also note: The l/mm resolution figures are subjective as they are judged by human eye using a test card like the one above - two testers will give different results. No lens is optically perfect, all cause some degradation. There are many other factors which affect the quality so I would not judge a lens on the l/mm rating alone. Some 1/3 format lenses that can resolve 480 TVL Bosch 3.3 – 8mm F1.4 Panasonic 3.8 - 8mm F1.4 Fujinon fixed F1.2 There are many others from Pentax, Tamron and Ernitec that will also do 480 but Computar 3.5 – 8 F1.4 will only manage 460 TVL. There is one popular vandal dome OEMed by many rated at 530 TVL and good low light - unfortunately it is usually fitted with a naff lens that only manages 390 by my tests. Same is true for many other cameras on the market.

Hi Rory, you still enjoying UK weather?

Oh ok, I guess that's the Euro spelling... kinda like colour... You can spell it either way wherever you are, both are correct- I wasn't being picky, just bein' silly