What specs to look for to get clearest picture possible?


Feb 20, 2020
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Rapid City SD
I just began researching in hopes of purchasing an 8 channel 4 camera CCTV system under $1000. What specs should I look for to insure I get the best picture possible in order to identify individuals? Or could someone point me to an article or video showing what to look for in a system? I would think the most important thing would be the angle size of lens. I planned to mount 1 to 2 cameras on my garage looking down a 30ft driveway. I'm not that interested in seeing my front lawn off to the sides. I have an old DVR system now and all it does is allow me to view my property being robbed without the ability to make out faces, which is more frustrating than no video to begin with. After a little research I believe I want a Dahua NVR recorder with POE. I was thinking I should get Amcrest (unsure if completely compatible with Dahua) 4k cameras but not sure about that anymore because I can't find 4k cameras in the higher end manufacturers. Do I need to be concerned about the processor, record rate 200mbps vs 320mbps, bite rate per channel, etc?
Dec 28, 2019
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New Jersey

Welcome to the land of video surveillance lunatics. Be sure to check the WiKI, in the blue bar at the top of the page. Study, carefully on a real computer, the Cliff Notes in there. There is also a lot of other good information for sizing a system and keeping it safe on the internet, foil the "phone home" features. Read, study plan, ask questions, revise plans and test before spending money. It'll save you time, frustration and money in the end. There's tons of reviews here on cameras, and NVRs to help confuse you even more when trying to make a decision.

Pre-packaged systems are usually a compromise, based on price. Some may actually be made by good manufacturers but features, and hardware items internally, get stripped out to get the cost down. Chasing megalpixels, resolution ratings, is not the magic bullet you may think it is. Frame rates get reduced, in the configuration of the camera itself, to reduce throughput. There's a way to calculate what lens size is needed in the WiKi as well.


IPCT Contributor
Dec 5, 2016
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IMO, there's a lot of good info in the Cliff Notes, located below. Be suer to read it from a computer though, it doesn't work well from mobile devices.

The size of the lens (2.8mm, 3.6mm) can have a big effect on the PPF (pixels per feet) value. Generally speaking, the smaller the lens value (2.8mm), the wider the image will be, but as you noticed the PPF value of someone standing further away from the camera doesn't give you enough detail to ID someone. The general recommendation is to make sure the PPF is 100+ at the distance from the camera that you want to ID someone with. You can use a tool like IPVM Camera Calculator V3 to drop a camera around a Google Maps image of your house, then move a "virtual person" various distances from the camera and see what the estimate image would look like (as well as see computed values, like PPF).

A lot of times achieving a PPF of 100+ requires using a varifocal camera. These are cameras whose lens can be electronically adjusted between a range of values, i.e. 2.7mm-13.5mm. If you were to zoom a varifocal camera into to a value of 13.5mm, the image would be pretty narrow, but the PPF further away from the camera would be a lot higher than if you had a 2.8mm camera looking the same direction. This can lead to the opposite situation of you seeing your front lawn off the sides, but not being able to ID someone... At 13.5mm, it may be vary well likely that you have enough PPF to ID someone, but the image is so narrow it doesn't include your entire driveway, much less your lawn. In situations like these, folks will use overview cameras that capture a wide area (so you can tell that something's going on), then specific cameras zoomed in tighter on key areas where you want to try and ID someone ... like on the driveway, side gates, front porches, etc. Keep in mind that varifocal cameras are not meant to be cheap PTZ camera replacements. Even though you can "zoom" the varifocal lens electronically, they're designed to be set when installed and not changed regularly. Every now and then you'll see someone that wants their varifocal lens camera to automatically zoom in tight when it detects someone. These are not the best cameras for that use case, especially considering that they can take 5-10 seconds to refocus sometimes... whatever you were hoping to zoom in on is probably gone by that point.

The other big thing (at least for most folks here) is how well the camera captures movement in low light with regards to blur. A PPF of 100+ is pointless if the camera blurs the facial details of the person because it's too dark for the image sensor. Getting blur free motion at night is one of the hardest things to do with security cameras, IMO. Be aware of this when you're reading reviews of cameras .. you really really want to see images or videos when something is moving. There have been a lot of images/videos posted that look great when nothing is moving, but when something does move, it gets uselessly blurred. Keep that in mind when you get your cameras and set them up... you will need to go out at night and move around and see how it looks.

Dahua and Hikvision make low-light camera models that use image sensors that aren't found in consumer grade models (Arlo, Ring, Amcrest, Lorex, etc). There are two particular image sensors that do the best (for the price). Look for cameras that use a 2MP 1/2.8" image sensor or a 4MP 1/1.8" image sensor. So far nobody's found any other image sensors (in affordable cameras, anyway) that do better in low light. And even as well as cameras with these sensors do in low light, it's not always a cake walk. There are times where you have to tweak camera settings (i.e. speed up the shutter speed) or sometimes even adding additional IR lighting to get the best shot.

If you go to the Dahua website , change the location to International, go to Products > Network Cameras > Pro AI Series > 4MP, the 4MP 1/1.8" image sensor in them makes them some of the best camera models that you can buy.

Here are some forum reviews of a few popular ones:
Review-OEM 4mp AI Cam IPC-T5442TM-AS Starlight+
Review - OEM IPC-B5442E-ZE 4MP AI Varifocal Bullet Camera With Starlight+

For models using the 2MP 1/2.8" image sensor, this varifocal turret model is becoming very popular:
Review-OEM IPC-T2231T-ZS 2mp Varifocal Starlight Camera | IP Cam Talk


IPCT Contributor
Feb 15, 2018
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Houston Tx
1) clear face identification depend on the mounting height of the camera, no more than 8 ft. If it is mounted under the eves of your house it is to high.
2) LUX, smaller is better, you can not compare LUX between different manufactures.
3) sensor size bigger is better. Sensor Size Chart
4) at night more light or IR, multiple source is better, less shadows
5) Pixels, stick with a 4 MP camera, 4k consumer cameras have not reached the quality of the 4MP. More megapixel is not necessarily better.
6) Lens , the bigger the lens value the less area covered but the more detail information in that area.