[samleo]

What causes purple fringing? Can it be avoided with shutter speed/exposure etc, or is it simply down to inferior quality lenses?

[silkstone]

It is mainly due to the lens, and better lenses tend to have less of it. It's most noticeable with dark objects (e.g. tree branches) against bright or blown highlights, and is often worse at the edges than in the middle.

Usually, keeping the aperture around the 'sweet spot' - typically f/8 or f/11 - will reduce fringing. It can also be removed in post-processing, although purple fringing can be more tricky than red/green fringing.

[VinnyP]

Just adding to what Silky says some of the latest cameras get rid of it automatically these days.

[Dave Canon]

If you use Raw files and have Adobe Camera Raw (Photoshop or Lightroom), you can largely correct this. You probably can with other Raw converters but I am not familiar with them.

Dave

[samleo]

Thank you all for that. I,ve never been troubled with it before , but a batch of pics I shot recently with my Sigma 70-210 at 210mm in poor light was absolutely plaqued with it. It was,in fact, purple and Photoshop only partly reduced it. I,ll have to watch my exposures with that lens very carefully in future!