What Camera Resolution and Lens a Factory Floor Needs
For most factory floors, 4MP cameras with a varifocal 2.8–12mm lens are the practical default: 2MP suits short-range overview, 4MP is the value sweet spot for identifying people and reading a machine indicator, and above 4MP rarely pays back. The lens — not the megapixels — sets your field of view. Match resolution to the pixels-per-metre your task needs, and stop.
More megapixels feel like the safe choice, so plants routinely overspend on 8MP cameras that deliver a blurry, dark image at night and chew storage — while a well-chosen 4MP camera with the right lens would have done the job for half the money. The number that actually matters is not megapixels or lens millimetres in isolation. It is pixels per metre (px/m) on the thing you need to see — a helmet, a face, a forklift lane, a machine's status lamp. This guide shows how to pick both, with the international standard and indicative Indian prices as of mid-2026.
Start with the task, not the spec sheet
The security industry has a published standard for "how much detail is enough": IEC 62676-4, known as DORI — Detection, Observation, Recognition, Identification. Each level maps to a minimum pixel density measured across one metre at the target's distance (Axis pixel-density white paper, IEC 62676-4):
| DORI level | What you can tell | Pixels per metre |
|---|---|---|
| Detection | "Something/someone is there." | 25 px/m |
| Observation | Distinctive features, clothing colour. | 63 px/m |
| Recognition | You know a person you've seen before; a helmet is/ isn't worn. | 125 px/m |
| Identification | Identify a stranger's face; read a small label. | 250 px/m |
This is the frame to buy against. Counting people, or "is that cell running or stopped?", needs only Detection-to-Observation density. PPE compliance (helmet on/off) sits around Recognition. Reading an unknown face or a small gauge needs Identification. Most factory-floor value lives in the Detection–Recognition band — which is exactly why 4MP is usually enough and 8MP is usually waste.
2MP vs 4MP vs higher: what the resolution buys you
Resolution is horizontal pixels to spread across your scene. The wider the area one camera covers, the fewer pixels land on each metre — so resolution and coverage trade off directly.
- 2MP (1080p, ~1920 px wide) — the volume workhorse. Across a 1920-pixel frame you get Identification up to ~7.7 m of scene width, Recognition up to ~15 m, Detection out to ~75 m (scene width, indicative). Fine for overview, aisle watch, gate detection, short-range PPE.
- 4MP (~2560–2688 px wide) — the value sweet spot. Same maths gives Identification to ~10 m, Recognition to ~20 m, Detection past 100 m. The extra pixels let one camera cover a wider bay while still reading helmets and faces. This is the default we recommend for a mixed factory floor.
- 6MP / 8MP (4K) and up — real gains only when you must cover a very wide area and keep Identification density, e.g. a long dispatch dock on one camera. Costs: bigger sensors that struggle in low light unless well-specified, and 2–4× the storage and bandwidth. On a dim shop floor, an 8MP camera often looks worse at night than a good 4MP one.
Those distances are scene-width limits set by pixel count — independent of lens. The lens then decides how far away that scene sits.
The lens sets your field of view — pick it deliberately
Focal length (millimetres) sets the horizontal angle of view. Lower mm = wider and closer; higher mm = narrower and farther (CCTV lens comparison, CCTV Camera Pros). Approximate horizontal field of view for common fixed lenses:
| Lens | Approx. horizontal FOV | Best for |
|---|---|---|
| 2.8mm | ~90–110° (wide) | Small rooms, overview, corners, packing/QC benches up close |
| 4mm | ~70–80° | General-purpose bays, aisles |
| 6mm | ~55–60° | Reaching a specific line or machine 8–15 m away with detail |
| 8–12mm | ~30–40° (narrow) | Long shot: a gate, a far machine, a specific gauge |
The rule of thumb: wide lens = wide coverage but low detail at distance; long lens = high detail but a narrow slice. A 2.8mm camera aimed across a large hall detects motion but won't identify a face at the far wall — pixels spread too thin. A 6mm reads a helmet at 12 m but sees only a corridor.
This is why a varifocal / motorised 2.8–12mm lens is the pragmatic buy for most positions: you tune the zoom on site to hit the DORI density that spot needs, instead of guessing focal length before installation and re-ordering. It costs more than a fixed lens, but saves a second truck-roll.
Indicative Indian prices (mid-2026)
Treat these as a planning band, not a quote — pricing varies by dealer, batch, and night-vision tier. Snapshot from Indian listings, mid-2026 (CCTV price guide, TheNcix):
| Camera (IP, fixed lens) | Indicative price (₹) |
|---|---|
| 2MP IP dome / bullet (CP Plus class) | ₹1,800–3,200 |
| 4MP IP dome / bullet (CP Plus class) | ₹3,500–5,800 |
| 4MP IP dome (Hikvision class) | ₹4,500–6,000 |
| 4MP motorised varifocal 2.8–12mm bullet | higher — get a quote |
The jump from 2MP to 4MP is often only ₹1,500–2,500 per camera (indicative) — small enough that 4MP is the right default for any position where you might later want PPE or face detail. 8MP is a larger step, worth it only for specific wide-coverage-plus-detail positions. Budget separately for the essentials: a PoE switch on a UPS, and your mounting choice (turret/dome for ceilings, bullet for walls).
Don't forget light — resolution can't fix a dark shop
Pixels are useless without photons. A high-megapixel camera in a poorly lit bay gives you a grainy, smeared image at exactly the moment you need it. Beyond the analytics case, adequate lighting is a statutory duty in India: the Factories Act, 1948, Section 17 requires sufficient and suitable lighting wherever workers work or pass (full text, India Code), with the Model Rules under §17(4) prescribing general illumination of not less than 65 lux over regularly-worked interior areas (Model Rules under the Factories Act, DGFASLI). Exact lux duties are set by each state's factory rules; 65 lux is the model figure. Spend on lighting and lens quality before spending on raw megapixels.
Two more specification notes for Indian buyers: cameras newly sold or installed from 1 April 2026 must meet BIS/STQC ER-01 security requirements (BIS CRS CCTV guidelines, crsbis.in), and if you want your cameras to work with third-party recorders and analytics, specify ONVIF Profile T conformance for interoperability (ONVIF Profiles).
How to decide, position by position
You don't buy one camera spec for the whole plant — you buy per position, per task:
- Name the task and its DORI level. Count = Detection. PPE = Recognition. Face/label = Identification.
- Measure the scene width you need that camera to cover.
- Pick resolution so pixels ÷ scene-width clears the DORI px/m for the task (usually 4MP).
- Pick the lens so that scene sits at the right distance — varifocal if unsure.
- Check the light at the darkest shift, not at noon.
Doing this by hand across 20–60 positions is where projects stall or over-buy. That "which camera, which lens, for which task, where" mapping is exactly the gap Mama closes: you record a short phone walkthrough of the floor, and it reads the space — bays, sightlines, hazards, machine positions, obstructions — then returns a floor plan plus a camera-placement plan that specifies resolution and lens per position against the task each one serves. You get the layout and the spec, in a day, without a site survey.
FAQ
Is 4MP always better than 2MP for a factory? Not always — but it's usually the right default. 2MP is fine for short-range overview, counting, and detection. 4MP costs only ₹1,500–2,500 more per camera (indicative) and gives you the headroom to identify people or read a machine indicator over a wider bay. Buy 2MP only where you're sure the task never needs more than overview.
Do I need 8MP / 4K cameras? Rarely. 8MP earns its cost only when one camera must cover a very wide area and still hit Identification pixel density — like a long dock. Otherwise it costs more, needs more storage and bandwidth, and often performs worse in the low light of a shop floor than a well-specified 4MP camera.
2.8mm or 6mm lens — which should I pick? 2.8mm gives a wide ~90–110° view for overview and small areas up close; 6mm gives a narrow ~60° view that reaches a specific line or machine 8–15 m away with detail. If you're unsure, buy a varifocal 2.8–12mm and tune it on site — it removes the guesswork and a repeat visit.
How do I know if a camera can identify a face at a given spot? Use the DORI standard (IEC 62676-4): you need about 250 pixels per metre for Identification, 125 px/m for Recognition (e.g. helmet on/off). Divide the camera's horizontal pixels by your scene width in metres — if it clears the threshold for your task, you're covered.
What else should I budget for besides the camera? A PoE switch on a UPS, cabling, the right mount (turret/dome for ceilings, bullet for walls), and adequate lighting — Section 17 of the Factories Act, 1948 requires it, and no resolution fixes a dark bay. Also specify BIS/STQC-compliant, ONVIF Profile T cameras so the system is legal and interoperable.