Why capture 14 stops of dynamic range if the final image is only SDR?
Asked 2/2/2024
5 views
2 answers
0
If a camera can capture around 14 stops of dynamic range but the final delivery is standard dynamic range, what practical benefit does that extra range provide? How is a wider-range capture mapped into a smaller display range, and why do people say it improves highlight roll-off? I'm asking mainly from a cinema perspective, but the same idea should apply to still photography too.
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
2y ago
2 Answers
5
A contrast ratio between 1000:1 and 4000:1 could be expected from an LCD screen. That's 10-12 stops. Given something more exotic like OLED and it goes up higher. 8 bit color is going to have at least 8 stops of theoretical (low precision) range if interpreted linearly, and more in practice thanks to gamma curves mimicking the exponential curve of color perception. Displays with more than 8 bits-per-channel have been a thing for decades. So it's possible to present more than 6 stops with relatively inexpensive hardware already.
Also if you're going to apply tone corrections to an image that will leave posterization unless you have more precision so capture is often at a higher bit depth which is more than capable of storing a greater dynamic range.
Even without HDR standards photographers can use HDR information, if only to choose which stops to display.
Originally by user108887. Source · Licensed CC BY-SA 4.0
user108887
2y ago
0
Generated from our catalog & community — verify before relying on it.
The extra dynamic range is valuable even if the final output is SDR because capture and display are different stages.
A camera raw file is not the finished image. Recording more range gives you room to edit: you can choose how to map highlights, midtones, and shadows into the smaller output range. That makes it easier to recover bright or dark detail, set exposure in post, and avoid clipping important tones.
It also helps image quality during grading. Tone and contrast adjustments can cause banding or posterization if the source has limited precision; higher bit depth and wider captured range give more headroom for those edits.
“Highlight roll-off” refers to how smoothly bright tones transition toward white. Sensors respond linearly until a channel clips, and once clipped, color and tone are no longer recorded accurately. With more captured range, you can compress bright tones more gracefully into SDR instead of having them hit a hard, abrupt ceiling.
Also, SDR displays are not necessarily limited to only about 6 stops in practice; many modern displays can show more contrast than that, especially with appropriate gamma encoding and better display technology.
Recommended products
UniqueBot
AI2y ago
Your Answer
Related Questions
What do camera dynamic range stops mean, and are they the same as EV on the meter?
How do I read a camera dynamic range chart across different ISO settings?
Why does the Canon 450D record 14-bit RAW instead of a higher bit depth?
Is Canon Log useful for still photography, or only for video?
How can measured dynamic range exceed a sensor’s bit depth?