Everything you need to know about sensor sizes

As a photographer, you may hear some terms thrown around that you aren’t fully familiar with yourself. Here, Clifton Cameras, retailer of Canon lenses, gives you the lowdown on camera sensors.

You may have heard people refer to their camera as full-frame or APS-C format – these terms relate to the size of the sensor that the cameras use to capture the image. A full-frame camera has a sensor that’s the same size as a 35mm film frame, 36x24mm, while an APS-C format camera has a sensor that is around the same size as the classic frame of APS (Advanced Photo System) film. We say ‘around’ because the film format actually measured 25.1×16.7mm, while the sensors are usually a little smaller at around 23.5 x 15.6mm.

If you move slightly further down the scale, you’ll see that Micro Four Thirds cameras have what is known as a Four Thirds type sensor which measures 17.3 x 13mm – and there are cameras like the Nikon 1 J5 that have 1-inch type sensors measuring 13.2×8.8 mm. Sensors smaller than 1-inch type are described as fractions of an inch, with 1/1.7-inch and 1/2.3-inch chips being common in compact cameras.

As a rule, high-quality images tend to be produced when a larger sensor is used. Using a smaller sensor can affect the quality of your images. That’s because the photo receptors, often called pixels, are larger and therefore able to receive more light. The more light they receive, the stronger the image signal will be and this helps keep down noise levels.

The larger the sensor, the more likely the image produced has captured a greater dynamic. This is because it’s capable of recording a wider range of tones in a single image. Another benefit of a large sensor is that at any given focal length and aperture there’s greater ability to restrict depth of field. That can be especially helpful with portraits when you might want to blur the background.

Bigger isn’t always better
However, despite the benefits on image quality when using a larger sensor, you should be aware of a few downsides that come hand-in-hand with a larger sensor. The sensor is the most expensive component in a camera, and consequently the price of a full-frame camera is much higher than that of a comparable APS-C or Micro Four Thirds model.

It goes without saying that a larger sensor is likely to take up more room and require bigger lenses which can make the whole system bulkier and heavier, especially if you are photographing hand-held.

What’s more, if landscape or macro photography is your thing, you may be more interested in having extensive depth of field rather than restricting it.

Here are a few examples of how sensor sizes differ between camera models: