Camera Lens, Field of View and Placement Workshop

1. Start with the operational requirement

Decide what the operator must be able to determine from the image. Axis guidance emphasises designing from the surveillance purpose and required detail.

2. Field of view is a lens/sensor relationship

Axis notes that focal length and sensor size determine field of view. Longer focal length narrows the view; wide-angle lenses cover more area but spread pixels over that area.

3. Resolution is not enough

A high-resolution camera aimed too wide or too far away can still provide insufficient detail on the target. Evaluate pixel density at the actual target plane.

4. Mounting angle matters

Very steep views can make faces, plates or other target details less useful. Position for the evidence you need, not merely for vandal resistance.

5. Account for lighting

Backlight, headlights, low light, IR reflection and changing daylight can alter image usability. Test the actual scene at relevant times.

6. Fixed, varifocal and zoom lenses

Fixed lenses suit stable known views. Varifocal/zoom capability provides adjustment but does not remove the need for a design target.

7. Avoid common physical mistakes

Do not aim through dirty glass at night IR, mount where foliage will grow into the view, or place the camera where nearby surfaces dominate exposure.

8. Use a commissioning target

At installation, stand a person/object at the required target location and confirm detail, focus and framing on the actual recording client.

9. Save evidence

Capture representative day/night images and record focal length/zoom position where available. These become the baseline for later complaints that the camera moved or focus changed.

Worked field scenario

A 4K camera covers an entire car park but cannot provide useful face detail at the gate. The issue is not simply resolution. Narrow the field of view or add a dedicated camera so enough pixels fall on the target at the required location.

Procurement questions before ordering

The ordering stage is where many field problems are created. Capture the following before selecting the exact product:

• Purpose of every camera view
• Lens/FOV and target distance
• PoE requirement and switch budget
• Expected bitrate and retention
• NVR/storage, VLAN and UPS design

Where a manufacturer compatibility list, rail matrix, supported-optics table or battery cartridge reference exists, record the exact source used for the decision. That gives the later installer evidence rather than a verbal assumption.

Fault-finding decision path

Separate image, network, power and recording faults. A black or poor image can be optics/lighting while a missing recording can be NVR/storage. Check PoE state, link, IP reachability, time, stream bitrate and recording status in that order rather than factory-resetting cameras first.

Keep a simple change log while troubleshooting: observation, action, result. If a change does not alter the symptom, put the system back unless there is a documented reason to retain it. This prevents troubleshooting from becoming an uncontrolled configuration drift.

Common mistakes that create repeat faults

Do not choose cameras from megapixels alone. Do not aim one very wide camera at an area where identification detail is required. Do not size storage from raw disk capacity or a single guessed bitrate, and do not UPS only the recorder while leaving the PoE switch unprotected.

A technically successful installation can still be a poor operational result if the next technician cannot identify what was installed, why it was selected, or how it was tested. Serviceability is part of infrastructure quality.

Acceptance and handover evidence

Save camera names, locations, switch ports, cable IDs, IPs, time source, recording profile, retention target and representative day/night images. Confirm playback and export, not just live view.

Use filenames, labels and port/bay identifiers that match the physical installation. Handover evidence should let someone who was not present at the installation verify the final state and repeat the important tests later.