How to Choose a CCTV Camera: Resolution, Lens, Night Vision

Megapixels are the first thing cameras are sold on and the first thing people overpay for. For general observation of a room or a yard, 2 MP (Full HD) is enough: you see what happens, who came in and where they went. To reliably recognise faces at an entrance or read price tags at a till, take 4 MP. 8 MP (4K) earns its price on wide views you need to crop details from: a parking lot, a perimeter, a whole sales floor.

Remember: more resolution means more archive and network load. An 8 MP camera fills a disk four times faster than a 2 MP one, and a weak recorder simply cannot record four of them. Resolution follows the zone's task, not "more, just in case".

Focal length defines what the camera sees. The standard 2.8 mm gives a wide angle of about 100° — the choice for rooms, entrances and small yards: everything is visible, but faces are distinguishable only up close. A 4 mm lens narrows the angle and "zooms in" — it covers corridors and approaches. 6–12 mm looks far and narrow: a driveway, a till from a distance, a plate at the gate.

A simple rule: one camera — one task. Trying to make a single camera "see everything and read faces" ends with it doing neither. For flexibility there are varifocal models with adjustable focal length and motorized ones you can retune remotely.

At night a camera works with IR illumination: the datasheet states 20, 30, 50 or 80 meters, and that is the honest limit of distinguishability, not "something visible". A yard needs 30 meters; a warehouse perimeter takes 50–80. ColorVu (Hikvision) and its analogues deliver a color night picture — the color of clothes and cars at night often matters more than extra megapixels.

For outdoor use check the protection class: IP66/IP67 against dust and rain, operating temperature down to −40° for our winters, an IK10 vandal-proof body wherever the camera is within reach. An outdoor camera without lens heating fogs up from inside in frost — the most common place to cut corners, and the wrong one.

An IP camera sends a digital picture over the network and takes power over the same cable (PoE), and supports analytics — person and vehicle detection, line crossing. Analog HDCVI/TVI is cheaper and runs over coax — a sensible choice when upgrading an old system. In new projects we almost always install IP: the price difference pays for itself in capability.

Small things that turn out to matter: a microphone if you need audio; a microSD slot for local recording when the network drops; on-board analytics (Hikvision AcuSense, Dahua SMD) that tells a person from a dog or a branch — without it, notifications from an outdoor camera become spam. We match cameras to the site's tasks and quote the kit for free — from Tashkent stock, under warranty.