Why Sensors Matter When Choosing a Surveillance Camera

When choosing a camera, it’s important not to neglect the sensor, especially if you plan to upgrade your cameras to HD, 4K and beyond. Here are five things you need to know.

1. Sensor size and resolution both matter for image quality

Imagine two camera sensors operating under the same conditions, each with two million pixels (2MP). The camera with the physically larger sensor will produce clearer images because the pixels are larger and therefore capture more light.

This is why a higher resolution doesn’t necessarily mean a ‘better image’ as if pixel count increases, but sensor size doesn’t, pixel size must decrease. In fact, you’ll find a HD 2MP camera can outperform a 3MP camera with the same size sensor in low light conditions. So ensure the balance between pixel count and sensor size is right for your requirements.

2. Your ideal sensor solution may not come as standard  

Despite their diminutive size, newer ‘micro pixel’ (< 3µm) sensors have a stronger low-light performance. However, though denser micro pixel counts on 1/3” sensors degrade image quality less, they cost more. They’re also not always available as standard, so this is something you’ll need to double-check in relation to your preferred camera.

3. Choose a lens to match your sensor

Lens and sensor performance should be well-matched. A low-quality lens can make a sensor upgrade pointless. To maximise camera capability, the lens should equal or exceed sensor performance.

4. Check that your sensor matches your display preferences

Sensors determine the aspect ratio. Many sensors have a non-standard aspect ratio. For example, 3MP sensors are typically 2048 x 1536, or 4:3. But because many control room monitors are 16:9 you either have to distort the image to fit or crop it – and it appears with black borders. Not desirable when whole scene awareness and image detail are priorities.

Alternatively, settings can be adjusted to display correctly in the 16:9 format by changing the resolution appropriately. The net result is often that, due to pixel size and density, the picture is of inferior quality than when using a 2MP sensor.

5. With 4K, sensors still matter and so does storage

With four times the pixel count (8MP) of standard HD, larger sensors, and a native 16:9 aspect ratio, 4K cameras have a lot going for them. Even where cameras still have some light sensitivity issues in relation to their sensors, the image is so good that any payoff is usually worth it.

With 4K, however, storage becomes a bigger priority. More 4K cameras (or higher) in operation means more data, especially when you start to factor in analytics. If you are considering 4K, you should also factor in more on-premise or cloud storage.