Camera Lens Calculator
2.8mm or 12mm? Enter how far away the target is and how wide a view you need — get the focal length, the nearest common lens, and what it means for faces and plates.
Find your lens
Common lens guide (1/2.8" sensor)
| Lens | View | Typical use |
|---|---|---|
| 2.8 mm | ~105° wide | Porches, small rooms, tight corners |
| 4 mm | ~84° | General coverage, 20–35 ft |
| 6 mm | ~54° | Driveways, medium distance |
| 8 mm | ~42° | Longer walkways, gates |
| 12 mm | ~25° | Faces/plates at 40–80 ft |
| 16–25 mm+ | <20° tele | Plate capture, long range |
Between sizes? A 2.8–12mm varifocal lets the installer dial in the exact view on-site. Pair this with the PPF calculator to confirm the detail level.
What the mm number really trades
Wide isn't free
A 2.8mm sees everything and identifies nothing past ~15 ft. Pixels get spread across the whole scene.
Zoom = evidence
A 12mm on a choke point (gate, door, drive entrance) puts every pixel where the face or plate passes.
Night changes it
IR range and glare shift at night. A lens that works at noon can bloom at midnight — always night-test.
Lens questions
What does the mm mean?
Focal length. Lower = wider view, less reach (2.8mm ≈ 105°). Higher = narrower, zoomed view with more detail at distance (12mm ≈ 25°).
2.8mm, 4mm, 6mm or 12mm?
2.8mm within ~15–20 ft, 4mm for 20–35 ft general coverage, 6mm for driveways, 8–12mm+ for ID at 40+ ft or plates. Use the calculator for your exact numbers.
Fixed or varifocal?
Fixed when you know the shot; varifocal (2.8–12mm) when you want the view fine-tuned on-site — best for plates and long approaches.
Want the lenses picked for you?
Hi-Tech specs the camera, lens and mounting height for every angle — Cleveland, Akron and Canton. Free plan review.