Every camera box at Costco shouts a megapixel number. 4MP. 8MP. 4K. 12MP. Some are advertised as “ultra HD” and leave the number off entirely. The assumption baked into the marketing is that bigger is better and you should always reach for the highest number you can afford.
The truth is more interesting. More megapixels can absolutely help — but only when paired with the right lens, the right mounting distance, and enough light. Pick the wrong combination and an 8MP camera produces worse usable footage than a well-placed 4MP one. This is a real-world guide to how many megapixels you actually need for the three jobs homeowners hire cameras to do: watching the driveway, covering the front door, and reading a license plate.
What a megapixel actually does
A megapixel is one million pixels on the camera’s sensor. A 4MP camera captures roughly 2688 × 1520 pixels per frame. An 8MP (4K) camera captures 3840 × 2160. Twice the pixels means you can crop further into the frame and still have usable detail — or cover a wider field of view without losing the ability to identify what you’re looking at.
The number that actually matters for forensic detail isn’t megapixels, though. It’s pixels per foot (PPF) on the subject. Industry rule of thumb:
- 25 PPF — detection. You can tell something is there.
- 50 PPF — recognition. You can tell it’s a person you know.
- 80–100 PPF — identification. A stranger’s face is identifiable to a court.
- 120+ PPF — license plate capture at standard angles.
Megapixels, lens focal length, and distance from the subject combine to produce PPF. Change any one of them and the answer shifts. That’s the whole game.
The driveway camera: 4MP is almost always enough
A typical Utah driveway is 20–40 feet from an eave-mounted camera. You want to see a car pull in, catch someone walking up, and generally know what’s going on. You do not need to read a license plate from this camera (more on that below).
A 4MP camera with a standard 2.8mm lens produces roughly a 100-degree horizontal field of view. At 30 feet, that covers about 70 feet of driveway width — enough to see two cars and the walkway. The PPF at that distance works out to around 55–65, which is comfortably in recognition range for faces and way more than enough for “a person in a dark hoodie walked across at 2:14 AM.”
Step up to 8MP on the same lens and you get more pixels to crop into — useful if you want to zoom in on a specific area after the fact. Step up to 12MP and you’re paying for pixels that are probably smaller and noisier in low light. The extra resolution helps during the day and hurts at night. Which brings us to the real issue.
Megapixels vs low-light performance: the trade-off nobody advertises
Here’s what camera boxes don’t tell you: on a fixed sensor size, cramming in more megapixels makes each pixel smaller. Smaller pixels catch less light. In a driveway at 11 PM with only a porch light, an 8MP camera can produce grainier, noisier footage than a 4MP camera with the same sensor size.
This is why professional installers push back on the “just get 4K” reflex. If your camera is watching a yard that’s dark most of the night, a 4MP camera with a larger pixel pitch and a good IR illuminator will produce more useful footage than an 8MP camera with the same body size. We covered this trade-off in more detail in the post on UniFi Protect vs Ring vs Nest, where sensor quality and bit-rate matter more than the number on the box.
If you do want high-megapixel cameras in low-light areas, pay attention to the sensor size (1/1.8″ is better than 1/2.8″) and look for low-light-specific features: BSI sensors, ColorVu, Smart IR. These make more difference than an extra 4MP.
The front door / doorbell: 4MP or 5MP, narrow lens
The doorbell camera has a harder job than the driveway one. You want to identify the face of someone standing 3–6 feet from the lens, clearly enough that you could show the footage to a neighbor or the police. At that distance, a 2.8mm wide lens wastes most of its pixels on the porch floor and the mailbox.
A 4MP camera with a 4mm lens aimed at door height gets you well over 200 PPF on a standing adult’s face. That’s identification-grade, and it’s the same amount of detail you’d get from an 8MP camera at the same spot. The extra megapixels do nothing when the subject already fills the frame.
What actually matters at the front door:
- Mounting height. A doorbell camera at waist height captures chests and chins. A PoE camera mounted at 6–7 feet captures faces.
- Backlight handling. Sun behind a visitor turns every face into a silhouette. Look for “true WDR” — not digital WDR.
- Frame rate. A porch pirate is on camera for 4–6 seconds. At 15 fps that’s 60–90 frames; at 30 fps it’s 120–180. More frames means more chances at a clean face shot.
This is also why we keep recommending PoE doorbell cameras over Wi-Fi battery models, and why the PoE explained post matters for anyone planning a camera install. A camera on a constantly-powered wire records 24/7; a Wi-Fi battery camera records in short clips triggered by PIR, and the face you needed often happens in the first two seconds before the clip starts.
License plate capture: megapixels matter, but not like you think
If you want to read plates off the street from a driveway camera, the number of megapixels on a wide lens is almost irrelevant. A 4MP camera with a 2.8mm lens pointed at a street 60 feet away puts roughly 10–15 pixels across a license plate. An 8MP on the same lens at the same distance gives you 20–25. Both are unreadable.
The right answer for plate capture is a dedicated LPR (license plate recognition) camera with a long focal length (12mm, 25mm, or a varifocal) aimed at one specific spot — the bottom of the driveway, or the curb in front of the house. Narrow field of view, high shutter speed, and often a visible-light-blocking filter that only passes IR so headlights don’t wash out the plate.
For LPR, 4MP on a telephoto lens outperforms 12MP on a wide lens, every time. The megapixels you need are dictated by the focal length, not the other way around.
What we install in Utah homes
A typical install in a Holladay or Draper home ends up looking like:
- Driveway and yard coverage: two or three 4MP PoE bullet cameras with 2.8mm lenses, mounted under eaves.
- Front door: a 4MP or 5MP PoE camera (or PoE doorbell) with a 4mm lens at face height.
- Side and back yards: 4MP PoE cameras, sometimes with built-in spotlights for deterrence and color-at-night footage.
- License plate (if requested): one dedicated 4MP LPR camera with a long focal length, aimed at the driveway entrance.
- Higher-resolution cameras only when they solve a specific problem — a large property where a single camera has to cover a wide area, or a commercial entrance where the client wants the option to crop in.
That mix typically comes in at eight to ten channels on a local NVR, each running at a bitrate that’s actually honest about the sensor — we covered why on-prem recording beats the cloud-subscription model in the $500 vs $5,000 security system post.
The short-term-rental exception
Short-term rental properties in Park City and Heber City have a different profile. Turnover is constant, the property is often unoccupied, and insurance claims can hinge on being able to prove who was in the driveway at what time. For those installs, stepping up to 8MP on the main driveway camera and adding a dedicated LPR at the gate makes sense — the marginal cost is small, and when something goes wrong, the extra pixels pay for themselves immediately. We’ve written about the specific challenges of short-term-rental security in Park City and Heber separately.
The megapixel lie
The biggest misconception we hear from homeowners who bought consumer cameras is that 4K is always better than 1080p. On the same sensor size with the same lens, it might be worse at night, storage four times larger, and produce footage that looks identical at typical viewing distances.
Resolution is one of five variables that decide whether you can see what you need to see. The other four — sensor size, lens focal length, low-light performance, and bitrate — often matter more. Get those right and a 4MP camera will embarrass a 12MP one.
Bottom line
For most Utah homes, 4MP PoE cameras on appropriately chosen lenses cover the front door, the driveway, and the yard with footage that’s identification-grade at the distances that matter. Step up to 8MP only where it specifically solves a problem: wide coverage on a large property, or a sensor that genuinely needs the extra pixels. Add a dedicated LPR camera if you want to read plates. And above all, ignore the number on the box when what you really need to evaluate is the whole optical path from subject to sensor.
Keystone Integration designs and installs PoE camera systems across Sandy, Holladay, Draper, and the rest of the Salt Lake and Utah valleys — matching camera resolution, lens, and mounting to the actual job each camera has to do. See our full service list or reach out for a site survey and a camera plan that’s right-sized for your property.