How to choose a home surveillance camera? After two rounds, I realized that night vision and focal length are the real deals, with pixel count coming last

Xiaolin handed over the keys to his new house last month and sent me three camera links to keep watch. All three links started with "8 million ultra-clear," and the night vision section read "Starlight Full Color." He stared at the pixels for a long time. I told him about the six heads we swapped out of our two wheels, and only then did he realize that the one he was staring at was actually the least troubled.

first round of tuition: at night it was all black and white

our first outdoor unit was installed in 2021. At the entrance of the yard, a certain brand of 2-megapixel infrared gun was cheap. The daytime footage was fine, but at night, the truth slipped out: someone walked into the yard, and the video showed a black-and-white human silhouette, with no visible clothing color, and the face was blurred. One night, the package was relocated. I checked the video and saw that figure, but I couldn't tell if it was the courier or the neighbor who had just visited.

later learned that infrared night vision relies on infrared lamps for supplementary light, so the image can only be black and white. Highly reflective items tend to overexpose. It's suitable for "checking if someone is there," not for "recognizing who."

another unexpected pitfall was bugs. When the infrared light came on, all the moth spiders swarmed toward the camera, weaving a web between the lens and the light. The motion detection triggered dozens of times throughout the night, and the alarm made my phone vibrate nonstop. After paying these two tuition fees, I finally started seriously studying the night vision section in the parameter table.

three night vision modes, first think carefully about what you want to see at night

nowadays, there are only three types of night vision for cameras, each with its own unique style:

the second round of phone replacements, I switched the one in the yard to full white light, and the effect was immediate: when someone comes in at night, you can clearly see the color of the clothes and the things they're carrying. The price was that the little white lamp stayed on all night, and during the first week, a neighbor subtly asked, "The light in your yard is pretty bright." Later, I changed the fill light in the app from "always on" to "motion detection triggered." When someone comes in, it lights up for a few seconds, but both the visuals and disturbance are taken care of.

I chose the Starlight class for the hallway car. There are voice-activated lights in the hallway. In the latter half of the night, when the lights go out, only a bit of emergency indicator light remains. The Starlight level can produce color with just this dim light, no need for supplemental lighting. But don't expect it to shine even in complete black—there's really no light at all, and it either automatically switches back to black-white-infrared or is just noisy. If you dare to write 'Starlight Full Color' on your e-commerce page, first check if that spot has any light at night.

also has a "smart switch": the starlight stays on normally, and when it detects people, it lights up the white light. If your budget allows, go for this—the front gate is the most suitable place.

focal length determines whether you recognize "someone" or "who"

this is an aspect even easier to overlook than night vision. My first yard camera was a 2.8mm wide-angle lens, allowing me to see the whole yard at a glance, which made me feel very safe—until I wanted to see the face of the person at the door. The courtyard gate is about six meters from the camera, with a 2.8mm horizontal field of view over ninety degrees. Faces six meters away appear as small as fingernails, and when zoomed in, it's all mosaics.

focal length is easy to calculate:

mnemonic is simple: do you want to see broadly or see clearly? At the main entrance, if you want to recognize faces or license plates, starting at 6mm; Inside the room, just watch the movement; 2.8mm is sufficient. My current yard setup is a 2.8mm device for global use, plus a 6mm nail at the door. Two units have different roles, which is much more realistic than expecting one machine to be both spacious and clear.

PTZ machines look good, but fixed machines are the real deal

Xiaolin sent me a link about a gimbal machine that can rotate 360 degrees and even turn in the direction the phone points to. It looks very high-end. I said, you should first think carefully about what you want to use it for.

the weak spot of PTZ machines: when it turns east, the west side becomes a blind spot. The most valuable thing about surveillance is actually 'looking back after the fact.' If something really happens, you can check the footage and see the camera was on the other side—how frustrating? The fixed bolt guards the angle for 24 hours without blinking—evidence collection has always relied on it.

PTZ machines are suitable for "real-time viewing": check if your child is doing homework or if the cat is scratching the sofa; you can manually rotate it in the app for a quick look. I keep a gimbal indoors, purely for remote eye contact, with all the important positions fixed to the camera.

Additionally, the gimbal is a mechanical structure; the motor gears are all consumable, and it's common for them to be stuck in place after two or three years or become unable to turn. The fixed machine has a simple structure and a much lower failure rate.

pixels and power delivery, don't overspend on these two

back to the 8-megapixel camera Kobayashi was eyeing. My view: For home use, 2 million (1080P) to 4 million is sufficient; for 8 million (4K), start with storage. A 1080P H.265 main bitstream is about 2MB, with 21GB per day; switching to 4K main stream for 8MB means 86GB per day, so four firsts mean about ten TB per month, and the hard drive cycles over a few days. It depends on the person and the car. 1080P is really enough. The extra details from 4K are mostly just storage troubles for yourself. I wrote a dedicated about stream and storage days, and reading them together makes it clearer.

power supply is determined by location, my lesson is:

• battery model: no wiring required, but battery life is directly linked to trigger frequency. The first model near my door was the battery model, labeled as half a year. It happened to be the year-end delivery peak season, with people coming and going, so I had to take it down and charge it every three weeks. You can use low-frequency spots like storage rooms or old yards, but don't make yourself troubled at the front door.
• Plug-in model: The most worry-free, provided the location is within reach of the socket.
• POE: One network cable for power supply brings data. If you install more, go this way. How to choose a switch, how to configure the network I have sorted out six after installing six parts, I won't repeat it here.

two minor pitfalls: First, the camera basically only recognizes 2.4G WiFi, and the phone connects to 5G to configure the network, but you can't find it in the device list. I've written about checking network connection; Second, before ordering the wireless model, check the signal at that location. If it's below -75dBm, don't make things difficult for them. Either use a different router or simply go wired. I've written about method for checking the signal blind spots before.

my current six heads, I just copied the spec list

After two rounds of elimination,

this lineup has been running for over a year. Here's a reference for you:

three things you don't want to skimp on when you buy it. First, I changed the default password that day. Cameras really scan the entire network segment. I checked every six heads in my house one by one, the most dangerous hole was the one they dug themselves. Second, where to decide where to add a camera—NVR, NAS, or SD card, NAS how to add a camera. I've fallen into the pitfall of an entire night where the video was completely empty. Third, remember to switch remote preview to a sub-stream, otherwise you'll be out and the traffic and lag will be unbearable. you can't see surveillance when going out, you've written about the five-layer check.

really want to save money. If you have old phones at home, you can just get one from a low-intensity slot like the Cat or Storage Room. I tried a Redmi Note 5 that has been gathering dust for a month for a month, and it works. Just don't expect it to be your main device.

Xiaolin's last order: a 6mm smart switch at the door, a 4mm infrared gimbal in the living room, and the two heads together cost less than 300 yuan. Pixels? He chose 4 million, and my main player at home still has 2 million. After reading this, just remember one thing: first think carefully about what you want to meet at night, then talk about anything else.