Summary

Camera selection determines the usefulness of a CCTV system. A high-quality recording and monitoring setup is worthless if the cameras cannot capture usable images in the conditions they are deployed in. The most common installation failures in UK CCTV are:

  1. Inadequate resolution at the point of interest (camera covers a wide area but cannot identify individuals)
  2. Inadequate IR illumination (camera appears to work but footage is too dark for verification at night)
  3. Wrong IP rating (moisture ingress damages the camera or reduces image quality)
  4. Wide dynamic range (WDR) not enabled or inadequate (bright windows or sun cause the rest of the image to appear black)

This article covers the main camera types and selection criteria for UK domestic and commercial installations. It does not recommend specific brands — focus on specification criteria that any camera must meet.

Key Facts

  • IP camera (Internet Protocol) — digital camera transmitting video over a network (cat5e/6 cable or wireless); standard for new installations; supports power over ethernet (PoE)
  • Analogue HD (AHD, TVI, CVI) — analogue cameras with HD resolution; uses existing coax cable infrastructure; cheaper than IP; common in retrofits; maximum practical resolution 4MP
  • PoE (Power over Ethernet) — single cat6 cable supplies both data and 12W power; eliminates need for separate power supply at each camera; requires PoE switch or PoE injector
  • Fixed camera — lens position and angle is set during installation; cannot be adjusted remotely; most common type
  • PTZ camera (Pan-Tilt-Zoom) — motorised; can be remotely directed and zoomed; useful for operator surveillance or auto-tracking; more expensive; mechanical failure risk over time
  • Fisheye camera — single camera with extreme wide-angle lens (180° or 360°); requires dewarping software to produce usable image; lower pixel density than fixed camera at equivalent resolution
  • Turret / eyeball camera — fixed camera in a dome housing; adjustable angle within the dome; common replacement for dome cameras in new build
  • Bullet camera — cylindrical housing; better for long-range IR; visible deterrent; more susceptible to vandalism than dome
  • IP rating (Ingress Protection) — two digits: first = solid particle protection (0–6); second = liquid protection (0–9K); IP66 = dust-tight + powerful water jets; IP67 = dust-tight + immersion to 1m for 30 min
  • IK rating (Impact Protection) — IK06 = 1J; IK08 = 5J; IK10 = 20J; choose IK08 or higher for exposed external installations
  • Lux rating — measure of light level; full moonlight ≈ 0.1 lux; indoor office ≈ 300–500 lux; camera colour sensitivity typically 0.01–0.001 lux; low-light cameras 0.0001 lux (Starlight/Darkfighter)
  • IR illumination — built-in infrared LEDs; provides illumination invisible to the eye; footage appears black and white in IR mode; range typically 20–100m depending on camera
  • White-light illumination — visible light LEDs; colour footage at night; better for identification; noticeable deterrent; higher power draw
  • Wide Dynamic Range (WDR) — corrects for scenes with both very bright and very dark areas; essential for cameras facing windows or external entrances; measured in dB (100–140 dB is good)
  • Lens focal length — longer focal length = narrower field of view = greater detail at distance; shorter = wider view = lower pixel density at distance
  • Varifocal lens — adjustable focal length; allows field of view to be tuned during installation; most external cameras now include motorised varifocal (remote zoom)

Quick Reference Table

Spending too long on quotes? squote turns a 2-minute voice recording into a professional quote.

Try squote free →
Camera Type Best Use Case Pixel Density at Range Typical Cost (unit) Key Limitation
Fixed dome / turret, 4MP Standard external coverage High at short range £60–200 Fixed angle; coverage limited to mounting point
Bullet, 4MP, long-range IR Perimeter, long distances High at target £80–250 Visible; more vandal-vulnerable
PTZ, 2–4MP, 25× optical zoom Operator surveillance, tracking Variable (zoom dependent) £400–2,000+ Mechanical failure; expensive; can miss events
Fisheye, 12MP Room overview, 360° lobby Low at perimeter £150–500 Poor pixel density for identification at range
Box camera + external lens Specialist applications High (lens-dependent) £200–600+ Manual adjustment; no IR built-in
Thermal camera Perimeter detection in total dark N/A (heat signature) £500–5,000+ No facial identification; detection only

Detailed Guidance

Resolution — How Much Do You Need?

Camera resolution is measured in megapixels (MP) or line pairs per picture height (TVL for analogue). For identification purposes, what matters is pixels per metre at the target distance — derived from the camera's total resolution and the field of view width at that distance.

Worked example: A 4MP camera (2688×1520 pixels) with a 2.8mm lens has a horizontal field of view of approximately 98°. At a distance of 10m, the field of view width is approximately 20m. Horizontal pixel density = 2688 pixels / 20m = 134 pixels/metre. This meets the ICO/Caltech recognition threshold (100 pixels/metre). At 20m, the width is approximately 40m, and pixel density = 67 pixels/metre — observation quality only.

Selecting resolution for your application:

Application Target Pixel Density Suggested Resolution
Perimeter detection (human presence at 50m+) 25 pixels/m 4MP with 12mm lens
Vehicle entry, plate reading (at 8–15m) 100+ pixels/m 4MP with 4–8mm lens, or dedicated ANPR
Pedestrian identification (at 5–10m) 100+ pixels/m 4MP with 2.8–4mm lens
Shop floor overview (15–20m wide) 50 pixels/m minimum 8MP fisheye or 4MP with wide lens
ATM/counter close-up (<3m) 250+ pixels/m 4MP with 8mm+ lens, short mounting distance

Lens Selection

Fixed focal length lenses (most common):

  • 2.8mm: approximately 90–100° horizontal field of view; wide; good for room coverage or close monitoring
  • 4mm: approximately 75–85° horizontal; standard external
  • 6mm: approximately 50–60°; narrower external, medium-range
  • 12mm: approximately 25–30°; long-range external, entry point detail
  • 25mm+: telephoto; for very specific long-range targets

Varifocal lenses:

  • Typically 2.8–12mm or 4–16mm range
  • Motorised varifocal (remote adjustable from NVR) is standard on most current IP cameras
  • Allows field of view to be tuned to match the specific scene during commissioning

Focal length rule of thumb for identification: If you need to identify individuals, the camera's horizontal field of view at the target distance should be no wider than 8m (for 4MP cameras). For a 4MP camera, this means:

  • At 5m: 2.8mm lens is acceptable (9m width, but 4MP gives ~300 pixels/m)
  • At 10m: 4mm lens is borderline; 6mm is preferred
  • At 20m: 12mm or 16mm required

IR and Low-Light Performance

UK outdoor lighting conditions: External cameras in the UK face significant low-light periods (winter evenings, overcast days). A camera rated at 0.01 lux in colour mode may switch to B&W IR mode even on overcast evenings in winter.

Key specifications:

  • Minimum illumination (colour mode): 0.01 lux is standard; 0.005 lux is better; Starlight/Darkfighter cameras achieve 0.001 lux or less
  • IR cut filter: cameras use an IR cut filter in daylight (for natural colour rendering) and switch to IR mode in low light; ensure the camera has an auto IR cut filter (ICR)
  • IR illumination range: 30m is minimum for standard external use; 50–80m for perimeter/long-range; 100m+ for specific long-range applications
  • IR LED array size: more LEDs = more range; but also more power draw
  • Adaptive IR: better cameras automatically reduce IR intensity as subjects get close to the camera, preventing overexposure ("bleached" image) of close subjects while also lighting distant subjects

White-light illumination: For colour footage at night, white-light LEDs are used. These are more effective for identification than IR (which produces B&W footage). However:

  • White light is visible — it alerts intruders that they are being observed (can be a deterrent, or can mean they simply avoid the lit area)
  • Higher power draw than IR
  • Causes harsh shadows; background falls into darkness
  • Some cameras combine IR and white-light (dual-light), activating white-light only when an activation is triggered

IP Rating Selection for UK Conditions

UK weather conditions include:

  • Rain (consistent, horizontal in wind)
  • Condensation (temperature cycling)
  • UV exposure
  • Coastal salt spray (coastal installations)
  • Frost

Minimum ratings:

  • External cameras: IP66 minimum; IP67 preferred
  • Vandal-resistant (ground floor, public-accessible mounting): IK08 minimum; IK10 for high-risk
  • Internal cameras: IP42 or IP52 is generally sufficient; IP54 for kitchen or bathroom areas
  • Coastal or very exposed locations: look for "marine grade" or "salt spray tested" additional certification

Common IP rating failures in CCTV:

  • Camera housing seals degrade over time (typically 5–7 years in UV/weather exposure); re-seal or replace
  • Cable entry point is the most common moisture ingress route; use cable glands with compression seals, not just push-through holes
  • Condenser drain (many cameras have a small drain hole at the bottom of the housing) must not be blocked

Wide Dynamic Range (WDR)

WDR is essential for cameras facing windows, doorways with bright exterior, or any scene with mixed bright and dark areas. Without adequate WDR, the camera adjusts exposure to the brightest area (e.g. a bright window), causing everything else in the image to appear black.

WDR is measured in dB; a higher dB value indicates a greater range of brightness the camera can handle:

  • 90–100 dB: basic WDR; adequate for indoor cameras
  • 100–120 dB: good; suitable for most mixed-lighting indoor/outdoor scenes
  • 120–140 dB: excellent; suitable for strong backlight conditions (entrance cameras, counters facing windows)

True WDR vs digital WDR: Many cheaper cameras advertise WDR but use a software-only approach (DWDR) that simply boosts shadows — this does not provide the same performance as true sensor-level WDR (which captures multiple exposures and combines them). Specify "true WDR" for cameras in challenging lighting conditions.

PTZ Camera Selection

PTZ cameras are justified when:

  • A wide area needs to be covered and an operator can be assigned to control the camera
  • Auto-tracking is needed (camera follows a moving target automatically)
  • A single camera must cover multiple areas that cannot be adequately covered by fixed cameras
  • Zoom is required to read details (e.g. licence plates at varying distances)

Specify PTZ cameras by:

  • Optical zoom: 25× or 32× for most commercial external PTZ; 40× for long-range or large-site applications
  • Preset positions: the camera should be configured with preset positions that it returns to when not being operated; covering the key camera zones
  • Auto-tracking: useful for open areas where targets move unpredictably; requires analytics; can cause false tracking of animals or vehicles in some environments
  • Positioning speed: important for operator use; slow cameras miss fast-moving targets
  • IP rating: as fixed cameras; PTZ cameras have more mechanical parts and are potentially more susceptible to moisture ingress

Frequently Asked Questions

Can I reuse existing analogue cameras on a new digital (IP) recording system?

Yes, using an analogue-to-IP bridge (AHD/TVI/CVI to IP converter) or by selecting an NVR that has hybrid inputs (accepting both IP and analogue HD cameras). However, analogue cameras are limited to approximately 5MP maximum resolution and do not benefit from most IP camera features (analytics, intelligent IR, cloud streaming). Reusing analogue cameras is cost-effective for short-term budget constraints, but in most cases full replacement with IP cameras provides much better value over a 5–10 year system life.

How many cameras do I need to cover a typical small retail unit?

A typical small retail unit (100–200m² floor area) usually needs 4–6 cameras:

  • 1 camera at each entrance/exit (entrance cameras at chest-height for face capture)
  • 1–2 cameras covering the main floor area (wide-angle overview, typically from corner mounting positions)
  • 1 camera at the till/counter (close-up; faces of people at the counter)
  • Optional: 1 external camera covering the external entrance and approach

For a layout plan, sketch the floor plan and mark zones: entrance, till, stock room access, areas of highest loss risk. Cover those zones with the minimum number of cameras that provides the required resolution. Avoid over-specifying (cameras pointing at empty walls or the ceiling) — it adds cost without security benefit.

What is the minimum specification for a system that satisfies most commercial insurers?

For a basic commercial property, most insurers require:

  • External cameras covering all entrance and exit points
  • Internal cameras covering high-value stock areas or tills
  • Resolution: adequate for identification (2MP+ IP cameras minimum)
  • Recording: minimum 28 days retention
  • Secure recording unit (NVR in locked room or housing)
  • Visible signage
  • System installed by a competent trade installer (NSI/SSAIB Gold for some insurers)

Check the specific insurer's requirements — they vary. Some specify exact camera resolution, retention period, or monitoring requirements. Always advise the customer to check their insurance documentation before commissioning the system.

Regulations & Standards

  • BS EN 62676-1-1:2014 — video surveillance systems; general requirements

  • BS EN 62676-4:2015 — video surveillance systems; application guidelines

  • BS 8418:2015 — detector-activated CCTV; image quality requirements for ARC-monitored systems

  • IEC 60529 — IP rating definitions (ingress protection)

  • IEC 62262 — IK rating definitions (impact protection)

  • UK GDPR / Data Protection Act 2018 — personal data requirements (see gdpr cctv ico obligations)

  • BSIA CCTV Operational Requirements Manual — industry guidance on camera selection and system design

  • ICO CCTV Guidance — image quality requirements for identification

  • Surveillance Camera Commissioner — code of practice for surveillance cameras

  • IPVM — independent CCTV product testing and comparison (subscription)

  • bs 8418 registered cctv — image quality requirements for police-response systems

  • nvr dvr storage sizing — recording equipment to match camera specification

  • gdpr cctv ico obligations — legal compliance for camera placement

  • nsi ssaib approval guide — installer approval for commercial CCTV