Is 4K Worth It,
Or Just Overkill?
More megapixels sounds like more security. Sometimes it is — and sometimes you're paying for detail you'll never use and a drive that fills twice as fast. Here's how to tell which.
"4K" is the number on the box that sells the camera. And for the right spot, it genuinely matters. But resolution is one of the most oversold specs in security — because more pixels only help if you actually need detail across a wide area, and they always cost you in storage. Here's the honest tradeoff.
The Numbers
5MP vs 8MP, Plainly
Ajax cameras come in two resolutions, and the difference is real but situational:
- 8MP is 4K (3840 × 2160). Maximum detail — it lets you hold sharpness across a wide scene, so you can still identify a face or read a plate at the far edge of a big driveway or lot.
- 5MP is 3K (2880 × 1620). Still high-definition and genuinely crisp — it balances image quality against storage and bandwidth, which matters more than the spec sheet admits.
Here's the honest rule: 4K earns its keep on wide, open areas where you need detail at distance. On a tight scene — a doorway, an entry, a hallway — 5MP is plenty, because the target is already close and filling the frame. Paying for 4K on a doorbell-distance shot is spending money on pixels you'll never look at.
The Catch Nobody Mentions
Resolution Costs You Storage
Every extra pixel is data that has to be recorded and stored. 4K footage eats drive space and bandwidth far faster than 5MP — often close to double. So "just get 4K everywhere" quietly becomes "buy a bigger drive" or "keep fewer days of footage." On a multi-camera system that adds up fast, and it's the cost the resolution marketing never shows you. It's worth planning against your recorder and drive from the start.
The Overlooked Factor
The Lens Matters As Much As The Megapixels
Here's what actually determines whether you can identify someone: how much of the frame they fill — and that's the lens, not just the sensor. Ajax cameras offer two:
- 2.8mm lens — wide (100–110°). Covers an open area, a yard, a whole driveway. Great for situational coverage, but a person at distance is small in frame.
- 4mm lens — narrower (75–85°). Trades width for detail, putting more pixels on a focused zone — a gate, a chokepoint, a doorway.
A 4K camera with the wrong lens can give you a worse identification than a 5MP camera with the right one. Resolution and lens and placement are one decision, which is exactly why "just buy the highest number" is the wrong way to spec a system — and why we design it around what you actually need to see.
Keep Reading
Related Guides
- Bullet vs turret vs dome — the housing side of the same decision
- How many cameras you need — coverage before resolution
- Do you need an NVR? — where all that 4K footage lands
Want The Right Detail
Where It Counts?
Tell us what you need to see — a plate at the gate, a face at the door, a wide yard — and we'll match resolution, lens, and placement to it. Detail where it matters, no wasted storage where it doesn't.