What is HDR in new smartphones ?

High-dynamic-range imaging (HDRI or HDR) is a technique used in imaging and photography to reproduce a greater dynamic range of luminosity than is possible with standard digital imaging or photographic techniques. The aim is to present the human eye with a similar range of luminance as that which, through the visual system, is familiar in everyday life. The human eye, through adaptation of the iris (and other methods) adjusts constantly to the broad dynamic changes ubiquitous in our environment. The brain continuously interprets this information so that most of us can see in a wide range of light conditions. Most cameras, on the other hand, cannot.

 

When You Shouldn’t Use HDR

Of course, as you’ve discovered, sometimes HDR actually makes your pictures look worse. Here are some situations in which HDR is better off ignored:

• Photos with Movement (see above): If any of your subjects are moving (or might move), HDR increases the chance of a blurry photo. Remember, HDR takes three pictures, so if your subject moves between the first and second shot, your final picture won’t look very good.
• High-Contrast Scenes: Some photos look better with stark contrast between the dark and light parts of the photo, like if you have a dark shadow or silhouette you want to highlight. HDR will make this less intense, resulting in a less interesting photo.
• Vivid Colors: If your scene is too dark or too light, HDR can bring some of the color back. However, if you’re dealing with colors that are already very vivid, HDR can wash them out.

An HDR Image :

 

When do we use HDR?

HDR can be used to take better photos under certain circumstances:

 

• Landscape photos: In a large open-area, the land and the sky displays great contrast, thus if your camera takes only one shot, it’s hard for the camera to process this kind of difference. With HDR, you can capture the details in the sky while keeping the exposures of the earth from being too dark, same goes for the shots to capture details on the ground.
• Portraits under bright lighting: We all know that good lighting is crucial for a great photo, but too much light on your subject can produce shadows, glare and other unwanted artifacts. HDR can remove these artifacts and make your subject better-looking
• Poorly lit or backlitted scenes: If your photo comes out to be a little dark (happens usually when the background is bright), HDR mode can bring out the details on the front part without sacrificing details and the lighting from the back.

When not to use HDR?
HDR is, of course, not omnipotent. It will be a nuisance under certain situations, for example:

• Shooting moving subjects: If you’re capturing images of a moving object (or bound to move), activating HDR will blur the end product. As HDR relies on the three shots, the motion between the first, second or third shot will ruin the desired effect.
• High contrast scenes: For certain scenes where the contrast is just right, activating HDR will decrease the contrast and render the image bland
• Brightly-coloured scenes: For certain scenes where the colours are bright and lively, activating HDR will make the colours turn dull and unattractive.