Can a single RAW file replace bracketed exposures for HDR?
Asked 6/1/2012
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2 answers
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I’m trying to understand whether shooting multiple exposures is really necessary for HDR. Since a RAW file often lets me recover roughly ±2 stops and contains more tonal data than a JPEG or what I can see on a monitor, it seems like one RAW image might already hold all the information needed for an HDR result.
If that’s true, then taking 3 bracketed RAW/JPEG shots would only add alignment issues without improving the final image. On the other hand, HDR is supposed to combine highlight detail from an underexposed image with shadow detail from an overexposed image.
So: when does a single RAW file suffice, and when do multiple bracketed exposures actually capture more dynamic range than one RAW can hold?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
14y ago
2 Answers
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HDR from a single RAW images does not add any dynamic-range than is captured. If the scene exceeds the dynamic-range of your camera, then no matter what you do the RAW will contained clipped channels on one or even both ends. Even if you have the best camera and use it at its optimal ISO setting, the most you get today is just above 14 stops of DR.
Taking a bracketed exposure let you capture a much broader range. Considering the range of modern DSLRs, you can easily bracket at with 5 EVs between each shot. That will expand 14 EV of DR to 24 EV.
Of course part of the question is the way to see this and that is where tone mapping come from. There is only HDR Display and it is very expensive, so everyone else must content with seeing something within the confines of normal dynamic-range (8 stops at most). So, yes, you end up seeing something which is not HDR but you still see things which had more range. Without being careful this obviously results in atrocious look HDR has become famous for.
Originally by user1620. Source · Licensed CC BY-SA 4.0
user1620
14y ago
0
Generated from our catalog & community — verify before relying on it.
A single RAW file can help you recover some highlight and shadow detail, but it cannot create dynamic range that the sensor never captured.
If the scene’s brightness range fits within your camera’s dynamic range, one RAW may be enough. But if highlights are clipped or shadows contain no usable signal, that information is gone and cannot be recovered later.
That’s where bracketed exposures help: each exposure captures a different part of the scene’s tonal range, and overlapping them can extend the total captured range beyond what one frame can hold. The number of shots depends on the scene, not the monitor or output format.
So your main assumption is only partly correct:
- RAW gives more editing latitude than JPEG.
- But RAW is still limited by the camera sensor’s dynamic range.
- Multiple exposures can capture more total scene range than one RAW when the scene exceeds that limit.
The tradeoff is practical: moving subjects or camera misalignment can make multi-shot HDR harder. But for very high-contrast scenes, bracketed exposures can preserve detail that a single RAW simply cannot.
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