Why do bright lights look oversaturated or inverted in my HDR brackets at night?
Asked 12/1/2015
1 views
2 answers
0
I shot a night scene in Times Square using HDR for the first time. I used AEB with three frames at 2-stop intervals (-2, 0, +2), mirror lock-up, and a self-timer. My exposure settings were 1/320 sec, ISO 800, f/11, 24mm. After merging and adjusting the HDR, some bright areas looked fake: highlights became oversaturated and some illuminated signs and car tail lights showed an inverted/negative-looking effect. Is this caused by flickering lights between bracketed shots, blown highlights, or HDR processing problems? What should I do next time to get a more natural HDR result in a busy night scene?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
10y ago
2 Answers
4
Software have trouble when there is motion in the scene to merge into an HDR image or even perform Exposure Fusion. There are two ways to deal with this:
- Increase your odds by shooting multiple brackets or multiple of each frame in a bracket.
- Take longer exposures. This is particularly needed for fluorescent lighting which cycles in north america at 1/60s (60Hz). Aim for at least 1/60s in your fastest shot, so 1/250s the the metered exposure and therefore 1/1000s for the third, assuming +2 EV steps.
The result will be quite different artistically but you can take option 2 above to the extreme using a very long exposure, something like 2, 8 and 30s. There will be more motion during frames but it will blur a lot and sometimes makes the results easier to merge. For such a dynamic scene as time-square, I would try to get quite a few sets and look at the results to decide which ones are worth processing.
Originally by user1620. Source · Licensed CC BY-SA 4.0
user1620
10y ago
0
Generated from our catalog & community — verify before relying on it.
The most likely cause is flickering light sources combined with short bracketed shutter speeds. In your set, the faster frames were likely short enough to catch LEDs/sign lighting at different points in their cycle, so the HDR merge saw mismatched brightness/color in the same areas. Motion in the scene can make merging harder too.
Also, if the darkest frame still clips bright signs or lights, HDR software may produce ugly highlight artifacts. Aggressive sharpening or local-contrast settings during HDR processing can make the “fake” look worse.
To improve it next time:
- Use slower shutter speeds so each frame captures a fuller light cycle.
- Consider shooting more brackets, or multiple frames at each exposure, to improve your chances of a clean merge.
- Make sure your darkest exposure preserves highlight detail in the brightest signs.
- Keep HDR processing conservative, especially sharpening/local contrast.
- In very dynamic scenes, longer exposures can sometimes help by blurring motion into something easier to merge.
So yes: flicker is a major suspect here, but clipped highlights and heavy HDR processing can contribute too.
Recommended products
UniqueBot
AI10y ago
Your Answer
Related Questions
How can I create a neon-lit night street look with deep blacks and controlled highlights?
How do I prevent illuminated building signs from blowing out in night city photos?
How can I photograph bright purple lights in a dark scene without blowing highlights?
Why do red lights in night city photos turn into big red blobs, and how can I prevent it?
How can I improve a night long-exposure photo of an outdoor fountain?