More Megapixels = Better Camera?
Could it be this simple?
Let’s start with the obvious. The higher the megapixel count on a CCTV camera’s sensor, the more detail it can capture, as long as the lens is sharp enough to resolve it. A 6MP camera, for example, records about 50% more pixels than a 4MP camera.
Obvious, right? That level of simplicity is what many camera manufacturers count on in their sales brochures. But could there be more to it? Read on.
More Pixels Isn’t the Same as More Detail
50% more pixels doesn’t mean 50% more usable detail. In security footage, what matters is pixel density, meaning how many pixels land across each metre of the scene. A typical 4MP camera is 2560 pixels wide and a 6MP camera is around 3072 pixels wide, so the 6MP camera gives you roughly 20% more detail across the image.
To double the detail on a face or number plate with the same field of view, you need four times the megapixels, for example going from 2MP to 8MP.
Why More Megapixels Can Be Bad
For a camera to form an image, light passes through the lens and onto the image sensor. How much light reaches the sensor depends mainly on the lens aperture and the size of the sensor. The more light the sensor receives, the better the image it can produce.
The problem comes when manufacturers pack more and more pixels onto the same size sensor. The available light is shared across more, smaller pixels, so each pixel receives less of it. Since a picture is made up of all these pixels together, the camera can struggle to get enough light to generate accurate colour and brightness for each one.
What does that mean?
Particularly in low light environments, a higher megapixel camera can produce a “noisier”, grainier image. Many cameras then apply heavy noise reduction to clean it up, which can smear away the very detail the extra pixels were meant to capture.
Take two different cameras with the same sensor size but different megapixel ratings, one 4MP and the other 8MP. In bright light, the 8MP camera will generally show more detail. But what if you want to use it at night or with dim lighting?
Suddenly, the image the 4MP camera produces might end up being clearer, because it doesn’t have the noise levels of the 8MP sensor.
Sensor size and technology matter here too. Larger sensors and newer low-light sensor designs have narrowed the gap, so a well-built 8MP camera can outperform an older 4MP model at night. That’s why the megapixel number on its own tells you very little.
Higher resolution also means larger video files, so it needs more recording storage and network bandwidth to go with it.
Our Solutions
With nearly two decades of experience, our experts can tailor a CCTV solution to meet your needs and budget.
The first step is a free site visit to understand exactly how your cameras will be used and placed.
Our staff will take into consideration all the factors that contribute to a great outcome:
- Quality of the lens
- Image sensor size
- Technology behind the sensor
- Light levels, light sources and infrared illumination
- Artificial intelligence (AI) in the camera and software
- Placement, including angle of view
- Resolution and pixel density needed for each area
- Video compression and bandwidth
- Recording and storage capabilities
From small, elegant solutions to powerful, multi-point networks, our team will design and install a commercial CCTV system that you can rely on day and night. You can see examples of our work on our recent projects page.
ISS partners with market leaders in security technology, such as Avigilon, and uses only the best CCTV products in our installations. We can custom design a quality CCTV solution that provides constant surveillance of your property when you are not around.
Call us today on 1300 992 090 or request a free, no obligation quote.