You have pick a good starting point.
Make sure your NVR can support the load from the cameras, Just because you have 6 free ports does not mean you can add 6 8mp cameras. check the specs on the NVR, it will have inbound and outbound data limits and processing limits.
More MP is not necessary better .
The bigger the sensor the better the night vision a 1/1.8 is better than a 1/2.7
Test your cameras location and camera selection before monting.
Read study plan before spending money.
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My standard welcome to the forum message.
Read Study Plan before spending money
Cameras are for surveillance to get information for after the fact.
Please read the IP Cam Talk Cliff Notes and other items in the IP Cam Talk Wiki. (read on a real computer, not a phone). The wiki is in the blue bar at the top of the page.
Read How to Secure Your Network (Don't Get Hacked!) in the wiki also.
Quick start
1) If you do not have a wired monitored alarm system, get that first
2) Use Dahua starlight cameras or Hikvision darkfighter cameras if you need good low light cameras.
3) Start with a good variable focus camera, so you test for the correct lens,lighting, camera placement.
4) use a VPN to access home network (openVPN)
5) Do not use wifi cameras.
6) Do not use cloud storage
7) Do Not use uPNP, P2P, QR, do not open ports,
8) More megapixel is not necessarily better.
9) Avoid chinese hacked cameras (most ebay, amazon, aliexpress cameras(not all, but most))
10) Do not use reolink, ring, nest, Arlo cameras (they are junk), no cloud cameras
11) If possible use a turret camera , bullet collect spiders, dome collect dirt and reflect light (IR)
12) Use only solid copper, AWG 23 or 24 ethernet wire. , no CCA (Copper Clad Aluminum)
13) use a test mount to verify the camera mount location.
My test rig: rev.2
14) (Looney2ns)If you want to be able to ID faces, don't mount cams higher than 7ft. You want to know who did it, not just what happened.
15) Use a router that has openVPN built in (Most ASUS, Some NetGear....)
16) camera placement use the calculator...
IPVM Camera Calculator V3
17) POE list
PoE Switch Suggestion List
18) Camera Sensor size, bigger is general better
Sensor Size Chart
19) Camera lens size, a bigger number give more range but less field of view.
Which Security Camera Lens Size Should I Buy?
20) verify your camera placement, have a friend wearing a hoodie, ball cap and sunglasses looking down approach the house, can you identify them at night ?
21) DO NOT UPGRADE your NVR or camera firmware unless you absolutely have a problem that needs to be fixed and known what you are doing, if you do you will turn it into a brick !!
Cameras to look at
IPC-T5442TM-AS-LED .
Review IPC-T5442TM-AS-LED (Full Color, Starlight+) - 4MP starlight
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Dahua IPC-T5442TM-AS-LED review
IPC-T5442TM-AS .....
Review-OEM 4mp AI Cam IPC-T5442TM-AS Starlight+ - 4MP starlight+
I
PC-HDW5442t-ZE .... Dahua IPC-HDW5442T-ZE 4MP Varifocal Turret - Night Perfomance testing -- variable focus 2.7 mm-12mm 4 MP Starlight
IPC-B5442E-ZE ......
Review - OEM IPC-B5442E-ZE 4MP AI Varifocal Bullet Camera With Starlight+ -- variable 2.7mm-12mm bullet
IPC-B5442E-Z4E .... bullet 8mm-32mm variable focus zoom 4MP
IPC-HFW7442H-Z .....
Review - Dahua IPC-HFW7442H-Z 4MP Ultra AI Varifocal Bullet Camera -- 4 MP variable focus AI
IPC-T2347G-LU ......
Review of the Hikvision OEM model IPC-T2347G-LU 'ColorVu' IP CCTV camera. (DS-2CD2347G1-LU)
IPC-HDW2231R-ZS ....
Review-Dahua IPC-HDW2231RP-ZS Starlight Camera-Varifocal
IPC-HDW2231T-ZS-S2 .
Review-OEM IPC-T2231T-ZS Ver 2, 2mp Varifocal Starlight Camera
IPC-HDW5231R-ZE ....
Review-Dahua Starlight IPC-HDW5231R-ZE 800 meter capable ePOE
IPC-HFW4239T-ASE ...
IPC-HFW4239T-ASE
IPCT-HDW5431RE-I ...
Review - IP Cam Talk 4 MP IR Fixed Turret Network Camera
IPC-T5241H-AS-PV ...
Review-OEM IPC-T5241H-AS-PV 2mp AI active deterrence cam
IPC-T3241-ZAS ......
Review-OEM IPC-T3241-ZAS 2mp AI Lite series Varifocal -- 2mp AI Lite series Varifocal
IPC-HFW2831T-ZS ...
Review-Dahua IPC-HFW2831T-ZS 8MP WDR IR Bullet Network Camera -- 8MP Bullet 1/1.8” sensor variable focus.
DS-2CD2325FWD-I
N22AL12 ............
New Dahua N22AL12 Budget Cam w/Starlight -- low cost entry
IPC-T2347G-LU.......
Review-Loryta OEM 4MP IPC-T2347G-LU ColorVu Fixed Turret Network 4mm lens & Junction Box -- 4MP ColorVu
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Review of the Hikvision OEM model IPC-T2347G-LU 'ColorVu' IP CCTV camera.
SD49225XA-HNR ......
Review - Dahua SD49225XA-HNR 2MP 25x Starlight + IR PTZ AI Camera with Deep IVS & SMD Plus -- 2mp startlight AI
Other dahua 4MP starlight
My preferred indoor cameras
DS-2CD2442FWD-IW
IPC-K35A
Review-Dahua IPC-K35A 3mp Cube Camera
IPC-K42A
Read,study,plan before spending money ..... plan plan plan
Do it right the first time saves money over having to do it twice.
Test do not guess