Quick answer: Use the exact model’s horizontal field of view and delivered recording resolution to estimate scene width and pixel density. The chart below is geometry for an assumed 5.4 mm active width, not a specification for every 1/2.7-inch camera. Pixel density helps shortlist a view but cannot guarantee identification. Confirm the project’s required standard edition and test the actual recorded task, mounting, lighting and motion.
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Why does the chart need the sensor, not just the focal length?
Focal length alone does not determine field of view. For an ideal rectilinear model, horizontal angle = 2 × arctan(active sensor width ÷ (2 × focal length)). At a defined distance to a perpendicular target plane, scene width = 2 × distance × tan(horizontal angle ÷ 2). Real optics, distortion, active crop and processing can differ; use the exact model/mode data and test the view.
A nominal optical-format name does not uniquely state the active width used by every camera/mode. This chart assumes 5.4 mm solely to show the calculation; it does not verify the sensor dimensions of any CASE SKU. Aspect ratio alone does not prove a larger active area or explain a wider published angle. Obtain the current exact-revision horizontal/vertical FOV, active mode and distortion/crop information before the camera schedule. Check the IP camera user manual and request missing exact-mode FOV data before specifying the view.
Illustrative horizontal angles for an assumed 5.4 mm active width
These ideal geometric values use an assumed 5.4 mm active sensor width. They are not model specifications or a guarantee that a zoom lens spans these exact angles. Assess vertical coverage and the actual mounted target plane separately; confirm the delivered mode and field of view from the exact model documents and a real view test.
| Focal length | Ideal horizontal angle | Use |
|---|---|---|
| 2.8 mm | 87.9° | Illustrative geometry only; confirm actual model/mode |
| 4 mm | 68.0° | Illustrative geometry only; confirm actual model/mode |
| 6 mm | 48.5° | Illustrative geometry only; confirm actual model/mode |
| 12 mm | 25.4° | Illustrative geometry only; confirm actual model/mode |
With that same assumed active width, moving from 2.8 to 4 mm narrows the ideal angle from about 87.9° to 68.0° and increases ideal horizontal pixel density by about 43% at the same distance/resolution. A 6-to-12 mm change doubles it under those assumptions, while reducing width. CS-I4KS L-2.8-12mm lists a motorized 2.8-12 mm lens, but its actual field-of-view range must come from the exact revision/mode, not this generic sensor assumption. Varifocal vs fixed lens explains the practical choice.
How wide is the scene at 16 ft (5 m), 33 ft (10 m) and 66 ft (20 m)?
Distance here is measured to a perpendicular target plane, not an arbitrary slant measurement to the ground. The table uses 5, 10 and 20 m and an ideal rectilinear lens with 5.4 mm active width. Actual mounting and distortion can change target detail across the scene. Values are rounded planning examples, not measured product performance.
| Focal length | Width at 5 m / 16.4 ft | Width at 10 m / 32.8 ft | Width at 20 m / 65.6 ft |
|---|---|---|---|
| 2.8 mm | 9.64 m / 31.6 ft | 19.29 m / 63.3 ft | 38.57 m / 126.5 ft |
| 4 mm | 6.75 m / 22.1 ft | 13.50 m / 44.3 ft | 27.00 m / 88.6 ft |
| 6 mm | 4.50 m / 14.8 ft | 9.00 m / 29.5 ft | 18.00 m / 59.1 ft |
| 12 mm | 2.25 m / 7.4 ft | 4.50 m / 14.8 ft | 9.00 m / 29.5 ft |
The ideal 2.8 mm example at 20 m spans about 38.6 m. That wide view may provide context, but whether a target can be recognized depends on delivered detail and conditions; width alone does not prove that nothing can be identified. In this simplified model, width scales with distance while pixel density falls. Test the required targets across the actual recorded scene, not only its center.
Estimate pixel density and identify the required standard edition
Pixels per metre = delivered horizontal recording pixels ÷ scene width in metres; pixels per foot uses width in feet. Use both where helpful rather than assuming all US/Canadian specifications use one unit. The familiar DORI table below is the 2014-era planning model, not an unqualified statement of the current IEC edition. IEC 62676-4:2025 is edition 2 and updates the operational categories. Identify the contract’s required edition and actual task before applying any threshold; analytics and thermal tasks require their own criteria.
| Historical 2014-era DORI label | Common planning density | Limit of this reference |
|---|---|---|
| Detection | 25 px/m ≈ 7.6 px/ft | Historical human-viewing guide, not guaranteed detection |
| Observation | 62.5 px/m ≈ 19.1 px/ft | Not proof of required detail in this scene |
| Recognition | 125 px/m ≈ 38.1 px/ft | Not a recognition guarantee |
| Identification | 250 px/m ≈ 76.2 px/ft | Not a current-edition compliance or identification certificate |
Illustrative geometry: a 4 mm lens with a 5.4 mm active width spans 13.5 m at a 10 m target plane. At 2560 horizontal recorded pixels, that is about 189.6 px/m or 57.8 px/ft; at 3840, about 284.4 px/m or 86.7 px/ft. Those numbers alone do not justify calling the image recognition or identification. Apply the actual requirement/edition and test motion, lighting, exposure, optics, compression and replay/export. The resolution guide helps compare pixel counts without replacing that acceptance test.
How do I read the chart against a CASE SKU?
Use the current exact SKU/revision sheet to confirm lens, horizontal/vertical field of view, active crop and delivered recording mode. The following catalog examples identify candidates and printed rows; none establishes a 5.4 mm active width or verified identification distance. Ask for missing field-of-view data before using a nominal chart in a proposal.
- CS-I4KS L-2.8mm: the catalog lists a 2.8 mm fixed lens and 2560×1440 at 25 fps. Use the actual horizontal recording mode and verified FOV for the density calculation; the chart does not establish a five-metre identification limit.
- CS-I4UV S-4mm: the catalog lists a 4 mm fixed lens and 2688×1520 at 30 fps. Its printed low-light figure is not proof of a specified face or plate task at a given distance; verify the exact mode, view and recorded scene.
- CS-I4KS L-2.8-12mm: the catalog lists a motorized 2.8-12 mm lens and 2560×1440 at 30 fps. Confirm actual FOV/zoom range and recorded performance at the chosen setting; a generic 12 mm chart does not establish a twenty-metre identification claim.
A printed illuminator range is not an identification distance. Verify the actual target, shutter/exposure, motion, lighting, reflections, mounting and recorded detail by day and night. IR range explained covers that distinction. Any demo equipment, return eligibility or testing arrangement needs written approval and the applicable terms; do not present a general ninety-day return promise.
The one-page version to print for the truck
Copy this calculation sheet into the project file with the stated assumptions. It is geometry for 5.4 mm active width at a 10 m target plane. The columns show density, not an identification limit. Replace assumed FOV with verified product/mode data and retain actual recorded acceptance results.
| Focal length | Ideal HFOV | Scene width at 10 m | 2560 px: px/m / px/ft | 3840 px: px/m / px/ft |
|---|---|---|---|---|
| 2.8 mm | 87.9° | 19.29 m | 132.7 / 40.5 | 199.1 / 60.7 |
| 4 mm | 68.0° | 13.50 m | 189.6 / 57.8 | 284.4 / 86.7 |
| 6 mm | 48.5° | 9.00 m | 284.4 / 86.7 | 426.7 / 130.0 |
| 12 mm | 25.4° | 4.50 m | 568.9 / 173.4 | 853.3 / 260.1 |
Using the page on a site walk
- Agree the target/task, positions, privacy boundaries, required recorded detail and acceptance method; identify the applicable specification edition.
- Measure mounting and target geometry, including height, angles and likely occlusions; a slanted ground distance is not the perpendicular plane used in this chart.
- Shortlist a supported lens/mode from exact FOV and delivered resolution; mark assumed values and obtain missing documents.
- Calculate scene width and density, then assess vertical coverage and detail across the full required target area.
- Test the actual recording/replay/export with representative lighting, movement and compression. Record pass, fail or pending honestly and revise the layout where needed.
What to tell your customer
We choose each view for the detail you need at the actual target positions. The chart helps shortlist the lens, but we confirm the exact model’s field of view and recording mode, then test the required footage by day and night. A pixel-density number is not an identification guarantee. Confirm the term, exclusions and claim process for the exact model and revision in writing.
FAQ
What is the field of view of a 2.8 mm security camera lens?
There is no single angle for every 2.8 mm security camera. With an assumed 5.4 mm active width and ideal rectilinear optics it is about 87.9° horizontally, but actual sensor crop, lens and mode can differ. Use the exact revision/mode FOV and a recorded scene test before commitment.
How many pixels per foot do I need for identification?
First identify the specified edition and task. The familiar 2014-era DORI identification guide is 250 px/m, about 76.2 px/ft; it is not an identification guarantee or an unqualified current IEC threshold. IEC 62676-4:2025 updates the model. Assess real recorded detail, viewing conditions and the agreed task; do not use one number as a certificate.
Is a 4 mm lens better than 2.8 mm for a business entrance?
It depends on the target and coverage. In the same ideal sensor/resolution geometry, 4 mm yields about 43% more horizontal pixel density than 2.8 mm at the same target plane, with a narrower view. That does not automatically move a real entrance into an identification category. Confirm exact FOV and recorded performance; retain additional context or task views where the tested design needs them.
Why does my night image show fewer usable pixels than the chart says?
Geometry counts sampled pixels, not necessarily usable evidence. Exposure, motion blur, lighting direction, IR reflections, compression, focus and replay conditions affect detail. Verify the required actual recording by day and night and improve the lens, position, lighting or settings where needed. A brochure illumination range and an arithmetic density do not guarantee the task. Use full color night vision explained to plan representative lighting and recording checks.
References
- Anabon: current model/revision manuals and documents
- IEC 62676-4:2025, edition 2: scope and publication details
- Axis: current 2025 pixel-density planning model and its limits
- Axis: separately identified 2014-era DORI model
