Chromatic Aberration

[Mils]

The Chromatic aberration removal does not seem to be responding in the develop persona. When I tick the box nothing happens.

I noticed in a video online (from 2018) that a grey box appears on screen (similar to when you press the Develop button) showing you that the image is being processed.

Sorry not a good image but all I could get - at least you get the idea what I am talking about.

I see absolutely no change in any images I try it out on. Nor do the de fringe sliders make any difference.

Does this mean I have no CA/fringing ??? or that this function is not working properly ???

I can see purple/green fringing and I sometimes get it blurred when I use the de fringe sliders

[carl123]

Can you upload one of the images it does not work on?

[Mils]

Here is one of them 

CA test image.CR2

[Ron P.]

It appears the CA correction dialog is tied to the Default Lens Profile setting in the Develop Assistant. If that is enabled, AP automatically applies CA adjustment to the image. You can see what it's doing by just checking/unchecking the CA box while looking at the Histogram. Disabling the Default Lens Profile in the Develop Assistant, you will get the CA processing pop-up.

[Mils]

MMMMM not sure I'm convinced with the result.

I have already tried disabling this function and yes I did see the histogram adjust but I'm not impressed with the results I get. To me the edges blur more than reduce the fringing. Is it me or is this all I should expect from this function? 

when I use the de fringe sliders it blurs even more !

[NotMyFault]

11 hours ago, Mils said:

MMMMM not sure I'm convinced with the result.

I have already tried disabling this function and yes I did see the histogram adjust but I'm not impressed with the results I get. To me the edges blur more than reduce the fringing. Is it me or is this all I should expect from this function? 

when I use the de fringe sliders it blurs even more !

Hi Mils,

The CA and defringe in Affinity are a tricky beast to deal with. You need to really experiment a lot until you find satisfying settings.

• CA correction results differ strongly to those of other apps. Canon DPP will almost automatically remove nasty colors even before you even activate the CA correction.
• Canon DPP removes the colors more (to grey), whereas Affinity removes the color cast and preserves the blue of the sky. So you have the choice.

Never the less:

• To be able to really spot these areas, i needed to zoom in to 400% or more this. Thus, for actual images, when looking at the final result, only experts will be able to see any difference. But then, these experts will be able to spot much more "imperfections".
• I cannot reproduce or confirm any blurriness from using CA correction or defringe adjustment in photo. The photo you supplied of an nature motive does not contain any hard edges at all. When i processed the image with either Affinity or Canon DPP, i could not find any blurriness except what to be expected (in areas edited/affected by filters).

To summarize:

• Other Apps have more "automatic" CA-correction, especially Canon DPP will remove CA drastically (to grey).
• Affinity Photo has a different approach, giving users the choice to leave some color remaining, but shifted from unwanted magenta to probably wanted sky-blue. As the blue is quite dark, this might unwanted, but can be corrected further.

And don't get me wrong - my knowledge to this topic is limited, based on .e.g. Wikipedia and lots of usage & experimentation with Photo. As a hobbyist on my own, we are prone to mix-up different causes of visible imperfections, and coming to wrong conclusions, often blaming issues to software bugs instead of own lack of knowledge.