HDR - what is it?

HDR is an integral part of many cameras and smartphones these days. You can find out how the technology works and what the advantages are in this practical tip.

HDR - what is it?

HDR stands for "High Dynamic Range" and is a technology to express colors and contrasts more vividly.

• It often happens that pictures are too dark or too light and do not have uniform brightness. It is often difficult to see details.
• HDR images offer uniform brightness as well as strong contrasts and colors compared to normal SDR images.

HDR - how does the technology work with smartphones?

With an HDR image, at least three images are taken simultaneously.

• Among other things, a normal, an overexposed and an underexposed image.
• The images are then merged into a software image that is never too light or too dark at any point.
• HDR also uses a color depth of at least 10 bit (standard is 8 bit), which is why colors shine more vividly and contrasts are expressed more strongly.
• The use of HDR is best suited for landscape shots and whenever the sun is dazzling: Over or under exposure can cause some details of the image to be lost. This is offset by HDR.
• However, the use of the HDR function is not always worthwhile: When taking motion pictures, blurred images are created because - as I said - several images are shot in succession.
• Even if a high contrast is desired, you should switch off HDR, otherwise the contrast will be washed out.

HDR on TVs

Nowadays televisions also offer the possibility to play back HDR films accordingly. A distinction is made between four different modes:

• HLG is the simplest form of HDR transmission. The quality is still very high, but can be played by most devices without any problems.
• The classic HDR10 uses a color depth of 10 bits: The colors are much stronger than with the conventional SDR.
• The HDR10 + usually also uses a color depth of 10 bits: However, this is dynamic HDR, so that the creators of a film can set the contrast information for each scene separately.
• "Dolby Vision" is best. With a color depth of 12 bits, 68 billion different colors can be displayed.
• However, HDR support for Dolby Vision has so far hardly been widespread among televisions: the screen technology cannot yet fully function and the television stations do not broadcast any programs in HDR.
• Users of streaming services and UHD Blu-rays can look forward to some films and series that support HDR.

In the next practical tip you will learn what the differences between UHD and 4K are.