Take your best shot – what is HDR?
By Adrian Toon, director of a2n.
The ‘HDR’ option is often seen on phone cameras, and it stands for ‘high dynamic range’.
This is a specific photographic technique which has been around for quite a number of years and has been used in all forms of photography.
Simply put, the camera sensor can only determine a range of sensitivity from light to dark and we use the aperture normally to control the amount of light depending on the ‘sensitivity’ that the sensor is set to, which is known as the ISO setting.
But on most images, there is some detail lost in the shadows and highlights, areas that are either too dark or too bright, where the detail is essentially lost on the sensor. HDR relies on three or more images being taken at the same time, at different aperture settings, below and above the normal exposure, therefore exposing the dark areas a little more, and the bright areas a little less.
The three, or more, images are then combined to offer the best detail across the whole of the picture, offering more detail in the final image.
The HDR option on a phone camera completes this work in a very short space of time and offers the user a picture with richer detail. For most general images you take, it is worthwhile leaving the HDR function switched on.