Comparison
4MP vs 6MP vs 8MP Security Cameras
Buying Guide
Quick answer
Use 4MP for efficient general overview, 6MP as a strong modern balance, and 8MP where a wider scene or additional crop detail justifies the storage and bitrate. Resolution alone does not guarantee identification.
Resolution comparison
| Resolution | Best fit | Advantage | Watch for |
|---|---|---|---|
| 4MP | Entries, corridors and general overview | Efficient storage and strong results from a good sensor | Less crop margin across wide scenes |
| 6MP | General modern home and business CCTV | Useful balance of detail, storage and product choice | Still needs the correct lens and lighting |
| 8MP / 4K | Wide driveways and important external views | More pixels for a broad scene and review crop | Higher storage/bitrate and no automatic night advantage |
What matters besides megapixels?
- Sensor size, lens aperture and image processing.
- Distance, field of view and how much of the frame the subject occupies.
- Lighting, shutter speed, compression and bitrate.
- Mounting angle and whether the scene needs overview or identification.
Why 8MP does not guarantee number plates
A plate may be only a few pixels high in a wide overview. Vehicle speed, angle, headlights, shutter and lens choice can defeat an ordinary 8MP camera. Use a dedicated ANPR design when plate capture is a requirement.
Use the SecurityWholesalers Resolution Simulator to compare scene expectations before ordering.
Worked example: front door and driveway
A 4MP or 6MP camera can be excellent at a short front-door view where the subject fills the frame. The wider driveway may justify 8MP or a varifocal lens. If number plates are essential, add a dedicated plate-capture camera rather than expecting the wide overview to perform two incompatible jobs.
How to compare footage fairly
Compare the same scene, lens width, time of night, shutter, bitrate and viewing size. A bright demonstration from one camera and a dark compressed clip from another is not a useful resolution comparison.
Resolution is useful only when the subject occupies enough pixels
A camera can have millions of pixels while the face or plate occupies only a tiny part of the frame. The useful question is pixel density at the target distance: how many pixels cover each metre of the scene, and how many pixels cover the object that must be reviewed? A wider field of view spreads the same resolution across more metres. A tighter lens concentrates pixels on a smaller area.
| Camera role | What it changes |
|---|---|
| Wide overview | Shows where activity occurred but gives each distant subject fewer pixels. |
| Tighter fixed lens | Improves detail at a chosen distance but sees less of the scene. |
| Motorised varifocal | Lets the installer tune framing after mounting. |
| Dedicated evidence camera | Separates face or plate capture from general overview. |
Sensor size, aperture and shutter can matter more at night
Putting more pixels on a small sensor can reduce the light collected by each pixel. A larger sensor and wider aperture can improve low-light performance, but image processing, lens quality and exposure settings still matter. Slow shutter speeds brighten a static scene while blurring a walking person or moving vehicle. That is why a bright paused image is not enough: compare recorded motion at the required distance.
| Specification | What it influences | Common mistake |
|---|---|---|
| Sensor size | Light collection and dynamic range | Comparing megapixels without comparing sensor area |
| Lens focal length | Field of view and subject size | Using a 2.8 mm overview for a distant identification job |
| Aperture | Amount of light reaching the sensor | Assuming a wide aperture removes the need for scene lighting |
| Shutter speed | Motion sharpness and exposure | Accepting a bright image that smears moving subjects |
| Bitrate and compression | Recorded detail and storage | Judging the live stream while the recording stream is heavily compressed |
Practical selection by scene
- Front door at short range: a well-framed 4MP or 6MP camera can be excellent because the face fills more of the image.
- Standard side path: 4MP or 6MP is often sufficient; night behaviour and angle matter more than extra crop margin.
- Wide driveway: 6MP or 8MP can help, but a varifocal lens or second camera may be more valuable.
- Long gate view: use a tighter lens and define whether the goal is people, vehicles or plates.
- Reliable plates: use a dedicated ANPR or plate-capture design rather than a generic resolution promise.
Storage comparison without false precision
Eight-megapixel cameras generally require more bitrate than comparable 4MP cameras, but there is no universal "days per terabyte" number. Codec, frame rate, scene motion, quality settings, smart codec behaviour and continuous versus event recording change the result. Calculate storage from the proposed recording bitrate for every channel, add margin and document the assumptions.
As a rough method, multiply the total recording bitrate in megabits per second by 10.8 to estimate gigabytes per day. For example, four cameras recording at 4 Mbps each use roughly 173 GB per day before overhead and variation. This is a planning approximation, not a guarantee; use the CCTV Storage Calculator for the proposed system.
How to perform a fair comparison
- Mount cameras at the same position or match their field of view.
- Use comparable frame rate, shutter and bitrate.
- Record a stationary chart and a moving person in daylight and full darkness.
- Export footage from the NVR rather than comparing phone screenshots.
- Review at normal size and at the crop needed for the real evidence task.
Frequently asked questions
Is 8MP always better than 6MP?
No. 8MP provides more pixels, but a 6MP camera with a better sensor, lens, lighting and position can produce more useful evidence.
Is 4MP enough for home CCTV?
It can be sufficient for general entries and overview scenes. Use higher resolution or a tighter lens where more detail is required.
Does 8MP use more storage?
Normally yes when other settings are comparable. Actual storage also depends on bitrate, codec, frame rate, recording mode and scene activity.
Need help selecting a system?
Provide the property type, camera positions, night conditions, required retention, network constraints and future camera count.