2.8mm vs 4mm Security Camera Lens: Which Should You Choose?
Compare 2.8mm and 4mm security-camera lenses by field of view, scene width, pixel density and best use cases.
The practical difference between 2.8mm and 4mm is not “better image quality.” It is how widely the camera spreads its pixels. On the same sensor, 2.8mm normally sees a wider scene; 4mm narrows the view and puts more pixels on a subject at the same distance.
2.8mm is better when coverage matters
- Small yards and patios.
- Short porches.
- Indoor rooms.
- Areas where the camera is physically close to the target.
4mm is better when detail matters farther out
- Driveways.
- Side gates.
- Narrow walkways.
- Entrances where you can sacrifice peripheral coverage.
Pixel density is the real comparison
If a 2560-pixel-wide stream covers 40 feet, it provides about 64 pixels per foot. If a narrower lens reduces the target scene to 25 feet, the same stream provides about 102 pixels per foot. Nothing about the sensor resolution changed; only the framing did.
Important: the exact FOV for 2.8mm and 4mm varies with sensor format. Use the camera’s published horizontal FOV or sensor dimensions, not a generic lens-angle chart.
Compare both setups with the coverage calculator.