lupy

I don't understand the point of the comparison, Yes a higher powered lense will show more detail, but a smaller field of view. It's impossible to compare camera quality in the two shots since they were from different angles at different focal lenghts. ususally, varifocal is better bacause you can adjust the field of view to balance detail and view area for your specific application, but you can achieve nearly the same effect with a handfull of screw in lenses, it just takes more time. Each camera is a little different in it's ability to handle different lighting and deliver good detail. The specs rarely tell the whole story, and screen shots can be rigged. If you are thinking about a security system, you should do enough research to understand what people are selling, maybe even buy a couple of cameras to fool around with. A properly installed system is going to set you back some $$, so it's worth spending some time to know what you want before you buy. After the neighbor was robbed, I installed a 4ch and then an 8 ch DVR system. I have probably $800 into it by now, and countless hours fiddling around. But I understand way more than I did when I started. I wouldn't even want to think about what it would have cost to have someone else put in the system.

You really need to list how long a run you are making. For very short runs, it's not as important, as you get longer, everything gets more critical.

there is something to be said for an in line fuse in these systems. It might not have saved you here, but a lot of low voltage wires are not very stong and a dead short can cause the supply or wires to overheat.

How long a run of cable do you have between the power supply and the camera? What size is your power feed line?

Just found this forum and wondering if someone has some experiance over volting cameras... I have a long driveway, about 500ft, and am concerned that someone is messing around at the end of it. I installed a ISC P540X day night camera, and am using cat 5 with a balun. Running 2 pair for power, one for video, and one in reserve for a beam break in the future. After install, I had problems with voltage sag during night operation so that the LED's were very dim. Testing at the camera and feeding it with a lab variable power supply, I see about 3.5 volts drop during day. At night it is much worse, needing about 18v at the source to get 11v at the camera. It's drawing about 500ma at night and ~100 in the day. While the LED's aren't full bright at 11v but it's reasonably usable, and I happen to have a wall wart that provides enough voltage to make it work fine at night. Problem is that when the current drops at daybreak, the camera will see 15.25v. I realize that these cameras have an internal regulator to compensate for variances in power supplies, but how much can they take before they start to fry?? Adding to the problem is that transformer power adapters drop voltage under load, so the day-night voltage swing is higher than with a regulated switching supply, but switching supplies produce a lot of noise, so what to do?? The simple solution is to just use this higher voltage wall wart, it seems like it Will work, but I am hoping for some reassurance the camera won't blow prematurely from the higher than normal day-time voltages. (15.25v DC) Thanks for any experiance you all might have.

Been busy a while, and though I would post an update, looks like the thread has taken on a life of it's own. As I understand that style of reg, it would require a voltage drop across the reg. The wall wart supply I have runs the camera at nite at a somewhat low, but usable 10.5 or so volts. Using a reg would drop the voltage a little more, requiring buying a different supply. Also, I had the Zener laying around, so it was a zero cost option. It seems to be working fine, though last week the neighbor dropped a tree on the line and then cut it in half with a chain saw..... He's a nice guy, but a little clumsy. Luckly I put a 1 amp fuse in the power supply line so nothing was damaged. I just spliced the cat5, replaced the fuse and i'm back in business. The heat from the LED's at night seem to be attracting spiders though, I have had to clean webs several times already, something I never saw with non led cameras. As far as running a proper thick wire, I just don't want to go with the expense or pain of running another 5-600ft of wire through the stickers and such.

Well, given that it's a 500ft run, through thick brambles and woods, I went with #2. I did calculate the wire resistance at ~23 ohm, so it's a pretty big factor. I ended up putting a 12v 10w zener and a big 10ohm resistor across the camera end of things. This gives ~13.2V at the camera during the day, well within what most wall warts supply, with a total draw at the wall of 250ma. At night, with the IR's, the camera voltage sags to 10.5V and about 400ma draw, so the Zener won't flow at night. This reduced voltage still gives enough brightness to see with. Actually, this brightness level is better than at full voltage, which tends to light up any mist in the air, making everything look foggy. (It's Seattle The wall transformer, (goodwill find) seems to work fine for the night, and at 400ma draw, it's well within it's 900ma at 16v rating. As far as switching power supplies, I tried a couple for powering the cameras and they all put noise into the picture, even with filtering. I know that the DVR uses a switcher, and that works fine. I am running video baluns (sp?) with long runs of cat5, so that might make them more sensitive to higher frequency noise from switchers. Anyway, it all seems to be working, and I tried all the failure modes I can think of without generating excessive heat, I am putting a small fuse on the camera power, just to be safe, and I mounted a small heat sink to the Zener. BTW, Like your avatar.. "I am not a number, I am a free man !"

The dc-dc converter is an option, and for the price, I might give it a try, upping the voltage would give a little better efficiency, though at 80% conversion efficiency, I would be burning about a watt at full load. Since this is a switching converter, I suspect it will add noise to the system. I realize that switching power converters are often used in cameras and transmitters, but they have been designed for a specific purpose, and proper filters have been added. I once tried powering my cameras with a 12v switching power supply that looked like a lap top charger. The results were very noisy, even with added caps and ferrite rings. The older heavy transformer wall warts provide much cleaner power, but unless regulated, the voltage floats around with load. Most have an open circuit voltage around 15v, and settle down to 12-14 with load. That's why nearly all security cameras have some sort of voltage regulation built in.

Wow, that's a bummer. I supose 24 from 9 is a lot more than I am talking about, but it's a good warning. I am thinking about putting a 12v or so zener diode at the camera with a resistor in series across the line. During the day, the diode will leak enough current to drop the line voltage to 13v or so, which should be safe for the camera. at night, the volatage will drop from the Ir's down to 11v or so, and the zener will stop leaking, so all the power will go to the lights. Thanks for the thoughts so far. Ken