It is simple LOL do not chase MP - do not buy a 4MP camera that is anything smaller than a 1/1.8" sensor. Do not buy a 2MP camera that is anything smaller than a 1/2.8" sensor. Do not buy a 4K (8MP) camera on anything smaller than a 1/1.2" sensor. Unfortunately, most 4k cams are on the same sensor as a 2MP and thus the 2MP will kick its butt all night long as the 4k will need 4 times the light than the 2MP... 4k will do very poor at night unless you have stadium quality lighting (well a lot of lighting LOL).
To identify someone with the 2.8mm lens that is popular in 8-kit NVR camera systems, someone would have to be within 13 feet of the camera, but realistically within 10 feet after you dial it in to your settings.
My neighbor was bragging to me how he only needed his four 2.8mm fixed lens 4k cams to see his entire property and the street and his whole backyard. His car was sitting in the driveway practically touching the garage door and his video quality was useless to ID the perp not even 10 feet away. Meanwhile my 2MP varifocal optically zoomed in to the public sidewalk provided the money shot to the police to get my neighbors all their stuff back. Nobody else had video that could provide anything useful, other than what time this motion blur ghost was at their car.
Here are my general distance recommendations, but switch out the Dahua 5442 series camera to the equivalent 2MP on the 1/2.8" sensor or equivalent Hikvision works as well.
- 5442 fixed lens 2.8mm - anything within 10 feet of camera OR as an overview camera
- 5442 ZE - varifocal - distances up to 40-50 feet (personally I wouldn't go past the 30 foot range but I like things closer)
- 5442 Z4E - anything up to 80-100 feet (personally I wouldn't go past 60 feet but I like things closer)
- 5241-Z12E - anything from 80 feet to almost 200 feet (personally I wouldn't go past 150 feet because I like things closer)
- 5241-Z12E - for a license plate cam that you would angle up the street to get plates up to about 175 feet away, or up to 220 with additional IR.
- 49225 PTZ - great PTZ and in conjunction with an NVR or Blue Iris and the cameras above that you can use as spotter cams to point the PTZ to the correct location to compliment the fixed cams.
You need to get the correct camera for the area trying to be covered. A 2.8mm to IDENTIFY someone 40 feet away is the wrong camera regardless of how good the camera is. A 2.8mm camera to IDENTIFY someone within 10 feet is a good choice OR it is an overview camera to see something happened but not be able to identify who.
So you will need to identify the distance the camera would be from the activities you want to IDENTIFY on and purchase the correct camera for that distance as an optical zoom.
Keep in mind that these type of cameras and NVRs, although are spec'd and capable of these various parameters, real world testing by many of us shows if you try to run these units at higher FPS and higher bitrates than needed that you will max out the CPU in the unit and then it bugs out just long enough that you miss something or video is choppy. My car is rated for 6,000RPM redline, but I am not gonna run it in 3rd gear on the highway at 6,000RPM...same with these types of units - gotta keep them under rated capacity. Some may do better than others, but trying to use the rated "spec" of every option available is usually not going to work well, either with a car or a camera or NVR.
I have a cheapo camera I use for overview purposes, but one of the cool things that camera has though in the gui is it shows the CPU usage. If I max out the FPS, bitrate, use it's motion detection and set it to middle sensitivity, the CPU maxes out 100% quite often. If I run it at 15 FPS with an appropriate bitrate and motion detection at a reasonable level, the CPU sits around 40%. I suspect even the more expensive cameras function close to this.
Wifi - forget about it. Wifi is problematic for surveillance cameras because they are always streaming and passing data. And the data demands go up with motion and then you lose signal. A lost packet and it has to resend. It can bring the whole network down if trying to use it through a wifi router. And then you are far enough away that you would not have full signal, and it will slow your whole system down. A member here tested wifi cameras and after 4 cameras, the system became unstable.
Unlike Netflix and other streaming services that buffer a movie, these cameras do not buffer up part of the video, so drop outs are frequent. You would be amazed how much streaming services buffer - don't believe me, start watching something and unplug your router and watch how much longer you can watch NetFlix before it freezes. Now do the same with a wifi camera and it is fairly instantaneous (within the latency of the stream itself)...
Most consumer grade wifi routers are not designed to pass the constant video stream data of cameras, and since they do not buffer, you get these issues.
These types of cameras are not GoPro or Hollywood type cameras that offer slow-mo capabilities and other features. They "offer" 30FPS and 60FPS to appease the general public that thinks that is what they need, but you will not find many of us here running more than 15 FPS; and movies are shot at 24 FPS, so anything above that is a waste of storage space for what these cameras are used for. If 24 FPS works for the big screen, I think 15 FPS is more than enough for phones and tablets LOL.
