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Also, you'd want to make sure the fabric actually absorbs IR. Some black fabrics reflect IR, and make the problem worse. I made a shade for one of my analog cams out of black plastic, and it lit up really brightly when the IR came on, washing out the view completely.

Yeah, I'm running an old Dell 3524P corporate switch that cost a little over $100 for 24 full power 100MB ports and 2 GB uplinks. This type of switch is not exactly user friendly - you update the bios over TFTP with a serial cable - and it sounds like a Harrier jump jet, but it's very robust, and I *never* run out of POE power.

Agree, and PC solutions are more flexible and upgradeable. My old dedicated boxes ran for years without any intervention at all, but I'm liking PC based systems these days, despite the OS update issues and security concerns. Performance depends on the solution. I'm fond of Blue Iris as a low-cost solution, but it requires a fair bit of horsepower if you're going to be running more than 6-8MP total at 10 fps (2nd gen i5 or better). This is mostly CPU power with reasonably fast hard disks, and not so much video power as a gaming pc would require.

I do plenty of that. I've done it a few times myself, but still not a ringing endorsement of Dahua support...

Check if IP Cam Viewer will work with it. It's the best of the smart phone viewers, IMO, and supports quite a lot of cameras.

The port-hole effect, known as vignetting, is caused by the lens being a smaller size than the sensor - for example, a 1/4" lens used with a 1/3" sensor. It also gives you a different field of view than matched lens/sensor combo - a 3.6mm lens that matched the sensor would give you more zoom and less fish-eye effect. You can roughly see what it would look like by drawing a rectangle over the image that excludes all the dark corners. You've hit on the several of the things that make a difference in lenses - the color fringing (called chromatic aberration) and the fuzziness at the edges compared to the middle. Getting rid of either of these costs more, so the lenses are a little pricier. I also found dust and lint inside some of my cheaper board cam lenses. This is easy to see as you're screwing the lens in, when the focus is completely fuzz. Any particles on the lens surfaces will rotate as you screw the lens in, and if they're internal, you won't be able to blow or wipe them away.

Again, this is my point. I have a Dahua brand camera, labeled Dahua. Bought it on ebay as a Dahua camera. Internal identification strings and model numbers are Dahua. I go to the Dahua website - no support. I have multiple Vivoteks, Areconts, a Messoa, an IQInvision, and two Avermedia boards, all bought used. I can go to any of these manufacturer's websites and get the latest software, manuals, find technical support, etc. Next problem - If I want a Dahua HFW-2100, how do I find one? I can get an (Dahua - lol, it auto-replaces with Dahua!) or an Empire, but these aren't listed as HFW-2100s, but as their own brand. This is a word-of-mouth connection; not exactly what I'd call inspired marketing. Finally, if I find out that the JoeCam Turbo 1.3 is an HFW-2100, order a few, and Joe closes down shop, I'm stuck holding the bag. Joe may not even be an authorized reseller, but only claimed to be. Apple? If I buy an iPad, Apple doesn't make me go to Best Buy or Target for my tech support and updates - I get it from them, even if I bought it used on ebay. Same with most tech gear these days. I understand Dahua's approach, and don't agree with it. No matter how you slice it, Dahua provides no technical support to users, and I think that's a big mistake. YMMV, as always.

Many small form factor (SFF) or thin PCs have limited space for hard drives, and many won't accept add-on cards, if you might want to go that way, so it's good to check. Also, many small Dells and similar PCs are designed on the edge of their heat handling capability, and adding extra hard drives can cause heat problems. I have some mini-ITX boxes that are quite small, but no room for RAID, second hard drive, video card, etc. I expanded several of them by putting the guts into micro-ATX boxes, which generally have more room, better airflow, etc.

Here's the comparison: http://www.cam-it.org/index.php?topic=3217.0 Now, I just realized this weekend that I didn't set the maximum exposure on the Dahua before making this comparison, and the Dahua probably had a longer exposure at low light, making it look better in comparison. I'll update it this weekend with maximum exposures matched. I'm liking the Dahuas, despite the mediocre software, but the lack of technical support is starting to look like a possible show-stopper.

Usually, if they specify IR, it means IR corrected, but some lenses block it instead. The description sometimes makes that clear, but not always, and either have to contact the vendor or take a chance. Some of my board cam lenses are marked MPIR. IR focuses at a different focal length than white light in a non-corrected lens, so the IR image is blurry if the daylight image is sharp. How much is dependent on the lens and aperture, but my Arecont 5MPs are very blurry when using IR with a non-IR compensated lens and a wide-open aperture. The IR compensation is done in the manufacture of the lens, similar to how they get rid of chromatic aberration, and can't be fixed with a filter or coating. A moving sensor would do it, but I don't know of any cctv cams that use this. Autofocus would probably work, for the cams that use it, but I don't have any experience there. When the filter moves, it just blocks or unblocks the IR. If the filter's out and IR is unblocked, you'd have good focus with white light, but the colors would be off due to the extra IR. Here's a page that demonstrates the difference in focus. If you look down at the pics of Legos, you'll see the with/without compensation comparison. http://www.infraredphoto.eu/Site/GentleIntro2.html

Best bet is to get some demos going on your home PC. If it handles the cams you're interested in without any problem, you can figure a cheaper PC will do, but if you hit high CPU utilization with your main rig, you'll need similar power for the NVR box. If you start out with one cam, some packages will let you connect the same cameras to multiple channels, so you can set up one cam 8 times to see how the system handles it.

Unfortunately, Dahua's customer support is non-existent. No firmware, no technical support, only what you can get through the vendor, and if that's not good - well, you're out of luck! They really need to do something about that if they want to play with the big boys.

You can do this, but it doesn't disable the IR LEDs. They always come on when it gets dark, even when the camera stays in daylight mode, so IR reflections may still show up. They also don't let you adjust the day/night switch sensitivity. Mine stays in day mode long after the main field of view is dark, due to a patch of sky at the edge of the field of view.

Also, if you're going to be using IR, be sure the lens is IR compensated. If not, the white light view can be fine, while the IR view will be blurry (or vice-versa). Some lenses labeled IR are IR blocking, not IR compensated...

You don't need an NVR card, only NVR software, since everything connects over the network. One network cable to your NVR PC is all it takes. Now, some NVR software is more efficient than others. You're talking about 24MP of cams, and at 10 FPS, that's quite a load for a cheap PC. Blue Iris is inexpensive, but needs a powerful PC to run that much - I'm not sure if a gen 3 I7 would handle 12 1080P cams at a decent frame rate. I've got an Aver NV6240e16 hybrid card in an i3-540 box, and it'll handle that many MP at 10FPS, no problem. I don't think the card is actually doing anything except acting as a dongle for the software, since I don't have any analog cams connected, but I could be wrong. Unfortunately, a 16 channel Aver card, bought new, is as expensive as a high-end PC. You can find them used pretty cheap, but you have to look and wait. I don't know if Aver sells their CMS-3000 software with a dongle for use without a card or NVR.

I haven't used the ST7501 software more than a few minutes, so can't answer that - maybe Vivotek can help. Blue Iris supports the Vivoteks nicely and isn't very expensive. It has a intuitive mouse-wheel zoom for both the record and playback windows.

I just got a 2nd Dahua, and am replacing some of my Vivotek IP8332 cams with them. The software is a lot less mature and flexible than the Vivoteks, while the image quality is definitely better, especially at night and in low light. Switching from bright to no light (like turning off a light) results in a black screen for 5-10 seconds while the IR filter decides to switch out (the IR LEDs come on right away). Going the other direction is not as bad, but if it's washed out, it takes some time for the auto-exposure to adjust. Firmware updates are problematic, though it sounds like your supplier may have a good setup for that. Getting actual technical or software support directly from Dahua is not good, and that's a big negative, IMO. They don't even have the manual for my 3MP bullet on their website. Reliability is still unknown - they haven't been out there long enough yet. We'll know more when these installations hit 1+ years. So, if they can get their firmware more mature and provide manufacturer direct software and technical support, they'll have a product much more ready for prime time. I'd try to copy Vivotek's functionality and support if I were them - they'd eat Vivotek for lunch if they could get that down.

If you wouldn't mind and have a chance, could you post a night shot pic from one so I can compare it to mine? That image has quite a lot of sharpening - too much for my taste. I don't know if you can adjust that in the setup, but I'd want to smooth it out a good bit if it were mine. Lots of modern cameras over-sharpen by default, and it really shows at night. I find it wipes out the detail, especially in low-contrast parts of the image.

You could try a Peltier cooler. These used to be popular for CPU cooling, and were still used in small car refrigerators 10 years or so ago. They're a bit current hungry and not super efficient, but the ones I used to use would frost up in seconds when they were unmounted from the CPU. Looks like you can get them up to a couple of hundred watts on ebay.

Is the less expensive one 1/3" or 1/4"? Usually, the black corners (vignetting) comes from using a smaller rated lens (like 1/4") on a larger sensor. With the cheap board cam lenses, I find that they're usually 1/4" if they don't specify the size.

My Dahua branded cam came with the daily reboot enabled by default, which I didn't notice until I saw it losing network comms every day at 3 am. You might want to check that and disable it; there could be a bug in the timing code for yours. What are you using to view/record? Mine went through a phase of briefly losing video every 90 seconds, but it was because my Blue Iris setup wasn't right for it. Can't quite remember the details; and will have to check my notes.

I bought a handful of bad IQEye cams some time back, and haven't been able to get any working yet through swapping parts. Some parts were easy to weed out - chips getting scorchingly hot and such - but others just don't want to play. One connects to the network and the picture pops in and out, but won't stabilize. So, if you have lots of time to mess around, and are a good troubleshooter and systematic record keeper, yeah, you might luck out. You'd better enjoy messing around with small electronics assemblies! Luckily, these were very cheap, but I'm about ready to toss them back to ebay, due to lack of time and them not being much fun any more.

If Lorex doesn't help, you might need to open it up and follow the leads back into the camera with an ohmmeter. If you have the same camera, that will also be helpful, as you can measure from the connector end to the camera end and figure out which is which.

If it never overheats with the 20' cable, and the 100' cable works fine for normal network use, it sounds like there's enough voltage drop across 100' of cat 5e that your camera's POE conversion circuit is having trouble. You could test this with a 100' cat 6 cable, which has slightly larger gauge wires than cat 5e. If it works with cat 6, it's likely a voltage drop issue. If not, it's back to the drawing board! This is all assuming the cable wasn't damaged when it was stapled, of course. That could be tested with a second 100' cat 5e cable.

I never used the TV Out on my NVR5000, but I can see 2 main differences between the pics you posted: - The TV Out has higher contrast and deeper colors, but lower resolution. The details on the bricks are not as good on this, even though the colors look better if saturation and contrast are what you want. - The main monitor image is lower contrast with better details. I actually like this one better. If you look at the bushes at the bottom, there's much better detail in this pic than in the TV Out. I've retired my NV5000, and I don't think my NV6240e16 has a TV Out signal...