Why do my Canon PowerShot RAW files show dark corners when the JPEGs don't?
Asked 4/3/2018
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2 answers
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I'm new to RAW processing and use a Canon PowerShot SX60 HS. With no filters, hood, or other attachments on the lens, some of my RAW files show dark rounded corners, while the in-camera JPEGs from RAW+JPEG mode look normal. The camera preview also looks normal.
Why does this only appear in the RAW file and not in Auto mode or the JPEG? Is there any way to spot this on the camera while shooting so I can adjust settings, or is it something I need to fix later in software? I'm processing the RAW files in darktable on Ubuntu.
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
8y ago
2 Answers
6
Many modern digital cameras are designed with the expectation that lens compromises will be... de-compromised... in RAW processing. That appears to be the case here.
The preview image is based on the JPEG rendering, which includes this processing. The RAW file, however, does not.
The amount of apparent vignetting will not be dependent on the scene, but on the lens zoom and aperture at which the picture was taken — that's why you're seeing differences in different situations.
The answer here is to use the lens correction module in darktable to apply this correction to your images as you process them. There's no other way around it — it is simply how the camera was designed.
Originally by user1943. Source · Licensed CC BY-SA 4.0
user1943
8y ago
0
Generated from our catalog & community — verify before relying on it.
What you’re seeing is normal for many compact/bridge cameras. The camera applies lens corrections when it creates JPEGs and the embedded preview, but the RAW file remains largely uncorrected. That’s why the camera screen and JPEG look fine while the RAW shows dark corners.
The effect depends mainly on lens design, zoom position, and aperture—not the scene itself. On cameras like the SX60 HS, manufacturers often rely on software correction as part of the system design.
So:
- Auto/JPEG mode: camera corrects it for you.
- RAW: your editor must apply the correction.
- Camera preview: based on the corrected JPEG preview, so it won’t reliably show the issue.
In darktable, use the lens correction tools/profile to correct distortion and corner darkening. Once distortion is corrected, the dark corners are typically cropped away as part of that process.
There usually isn’t a reliable in-camera warning for this when shooting RAW, because the preview itself is corrected. Practically, the solution is to expect this in RAW and apply lens correction during processing.
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AI8y ago
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