Does white balance affect dynamic range?
Asked 1/29/2014
1 views
2 answers
0
Is there any real relationship between white balance and dynamic range? I’m asking both about what the camera sensor captures in a raw file and what happens in the final processed image.
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
12y ago
2 Answers
2
The white balance you select impacts the dynamic range for particular colors in the final output only. When you adjust the white balance of an image, you are not actually adjusting how the sensor picks up colors of light, but rather how each signal is weighted.
If, say, red is weighted more highly than green, then the limit to how high your red value can go is lower in terms of actual measures. A value of .85,1,1 would be white since the .85 red is being treated as 1. Any value above .85 would exceed the color space and so that amount of dynamic range of the sensor is effectively lost as it is impossible for the camera to sample enough green and blue to properly resolve a white object that reads a value of 1 for the red pixels.
The actual dynamic range the sensor picks up is unaltered, but later white balance adjustments render one color to have a wider range than the others, the dynamic range for those colors has to be limited to make a natural looking image.
This is why, for example, when a photo is taken underwater (where there is far more green and blue light than red) the colors end up looking muted and noisy if you try to properly white balance. Under those kinds of conditions, a white object will have blue and green fully exposed, but the red will only be at 10 or 20%. In order to achieve a white balance, that 20% range has to be expanded to fill the whole 100%. This expansion means that the effective dynamic range of the red color is much more limited. It may be expanded to match the level of intensity of the other colors, but far fewer intensity levels are represented.
(As a side note, one could argue this isn't really the dynamic range, but it depends on how you look at dynamic range. If you are looking for what is the brightest and darkest detectable value, then the dynamic range isn't altered by this. If you are looking for the number of distinguishable values within the image, then it is, since the usable range of the sensor is impacted by the white balance even if there wasn't any information in that range.)
Originally by user11392. Source · Licensed CC BY-SA 4.0
user11392
12y ago
0
Generated from our catalog & community — verify before relying on it.
For the raw capture, essentially no: white balance does not change the sensor’s actual dynamic range. Dynamic range is the range of light levels the sensor can record before shadows fall into noise or highlights clip, and that is fixed by the sensor/exposure.
White balance is a color scaling adjustment. It changes how the recorded red, green, and blue channel data are weighted to render neutral colors correctly; it does not change how much light the sensor captured.
However, in the final rendered image, white balance can affect the effective headroom of individual color channels. If one channel is boosted strongly, that channel may reach its output limit sooner, so you can lose highlight detail in that color during processing/output even though the sensor’s underlying capture dynamic range was unchanged.
So the short version is:
- raw sensor dynamic range: not changed by white balance
- processed/output channel headroom: can be affected by white balance adjustments
Recommended products
UniqueBot
AI12y ago
Your Answer
Related Questions
Are there RAW-like files that capture more dynamic range than a single camera RAW?
Why do RAW files allow more editing flexibility than JPEG or PNG?
What does “linearization” mean in RAW processing?
Does Lightroom use the full editing latitude of RAW files?
What is dynamic range, and why does it matter in photography?