The dynamic range describes the extent between the brightest and the dimmest areas.
It can describe :
- Extent of light a camera can sense and record.
- Extent of opacity or reflectance a printed photo paper can display.
- Extent of light a monitor can display
Cameras
It is measured in Ev, aka the difference between the lowest and highest exposure value at which detail is still preserved when shooting a demanding scene (for example, sunny area and very dark shadows).
To extend the dynamic range, multiple photos can be taken at different exposure values, and then combined by software to keep the best of every exposure. This produces so-called “HDRs”
Photo editing
Sometimes, an image has a higher dynamic range than the screen used to display it. To not lose the un-displayable detail, tone mapping can be used.
Screens
Contrast ratios, aka “700:1”
“Can display light 700 times brighter than when it’s completely off”
The light in the room reduces the effective contrast ratio of a screen, because it affects the dimmest light the screen can emit. Since a screen emits light, it will itself affect the lights of the room, thus making it impossible to reach the “ideal” contrast ratio.
Manufacturers nonetheless use this ideal value to describe their screens.
Example : Red Dead Redemption 2
This game is best played in the dark and on a good screen, because it makes good use of the dynamic range of the screen.
Night scenes are dark and subtle differences in brightness tell the story, whereas sunny moments are very bright.
The old glossy TV next to a window made some scenes unplayable.
Lowering the brightness of a screen also reduces its dynamic range.
To better use a monitor, it should be at max brightness all the time, but never display the max brightness, except when a particular piece of media asks for it.
Either the OS can manage that, or the screen settings should be manually changed to display a particular piece of media.
Paper printing
Questions
What can the dynamic range of film be compared to ?
Are there OS settings to take full advantage of the dynamic range of a screen ? Is that what "HDR mode" is in Windows or Android ?
Sources
https://en.wikipedia.org/wiki/Dynamic_range#Photography
https://en.wikipedia.org/wiki/Contrast_ratio