Can a camera body correct lens defects in software?

Asked 1/16/2011

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Some lenses are costly because their optics are designed to minimize aberrations and other defects. If a camera knows the characteristics of a specific lens, can the camera body and image processor correct those defects automatically? Which lens problems are realistically fixable in-camera, and which are still difficult or impossible to correct well in software?

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

15y ago

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There are a limited set of defects that can be corrected in software, lateral chromatic aberration, yes, but not longitudinal chromatic aberration. Lateral CA results in the component colours of light being displaced radially across the sensor. This can be corrected by simply warping each colour channel slightly differently. Longitudinal CA causes out of focus areas near strong lights to be tinted either green of magenta depending on whether they are in front of behind the plane of focus. This is much harder to correct as you need to know 3D information about the scene.

Some cameras are now offering lens corrections based on a database of corrections tailored to each lens. I think these are limited to barrel distortion, lateral CA and vignetting.

You'd think the manufacturers would be the best source of this sort of information but I would image crowd sourcing the parameters on the net would be more effective as there are some very dedicated people around taking that sort of measurement.

Originally by user1375. Source · Licensed CC BY-SA 4.0

user1375

15y ago

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AI Answer

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Yes—up to a point. If a defect can be corrected in post-processing, it can generally be corrected in-camera too, and many cameras already do this using lens-specific correction profiles.

The defects most commonly corrected well are:

  • barrel/pincushion distortion
  • vignetting
  • lateral chromatic aberration

These are relatively predictable and can be handled by remapping the image or adjusting color channels.

Some problems are much harder or not truly reversible in software, including:

  • longitudinal chromatic aberration
  • softness/loss of resolution from poor optics or focus errors
  • flare and ghosting from reflections inside the lens

Those issues either lose information or depend on 3D scene depth and focus relationships, so software can only reduce them somewhat, not fully undo them.

So the idea is technically possible and already common, but it only works well for a limited set of lens defects. Good optical design is still necessary because software cannot fully replace missing detail or remove all optical artifacts.

UniqueBot

AI

15y ago

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