Feedback on DORI-based Camera Selection (Front Door & Garage) - Did I Overkill or Misunderstand?

[phdelodder]

Hello everyone,

I've been going down the rabbit hole and trying to apply the DORI methodology for my camera selections, with a specific focus on achieving Identification at my critical choke points.

I've read and tried to understand the core concepts in these two threads:

• The Importance of Focal Length over MP in Camera Selection
• I want 2.8mm cameras everywhere to see everything - This is why you need specific FOVs with purposeful focal lengths

Based on my desired Identification distance and FOV, here are my proposed camera selections. I'd appreciate feedback on whether these are overkill, or if I have completely misunderstood the application of DORI/focal length concepts, particularly for the longer 15m range.

I have attached an image showing the general layout for reference.

Use Case 1: Front Door/Entry Point

• Goal: Identification of a person (face/features).
• Critical Distance: A few meters (let's say 3-5m).
• Required FOV: Approximately 60° (to cover the landing/walkway).
• Selected Cameras (4MP):
  • HIKVISION DS-2CD2346G2H-I(U)
  • Dahua IPC-HDW3441EM-S-S2

Use Case 2: Garage/Driveway Coverage

• Goal: Identification of a person (face/features) entering the area.
• Critical Distance: Approximately 15 meters.
• Required FOV: 90° (to cover the full width of the driveway).
• Selected Cameras:
  • 4MP (Varifocal for dialing in focal length):
    • HIKVISION DS-2CD2H46G2-IZS(2.8-12mm) — My reasoning here is to use the varifocal to dial in the focal length (likely 6mm-8mm) necessary to hit the required Identification PPI at 15m, as DORI calculators suggest.
    • Dahua IPC-HDW3449T-ZS-IL
  • 8MP (Vari focal, High-Res):
    • Dahua IPC-HDW3849T-ZS-IL
    • Hikvision DS-2CD2H86G2-IZS

My main question is: For the 15m / 90° requirement, are the 4MP or 8MP cameras listed appropriate, or have I over-spec'd them? Given the distance and wide FOV, I know I need higher pixel density/a longer focal length, but am I focusing too much on the MP count instead of the lens?

Any guidance on my selections would be greatly appreciated!