>I think FoCal is handling this exactly right. When focus is >“perfect” you will see the most apparent fringing. Even going >slightly out of focus will make the appearance of fringing go >away because the difference in focusing for the three colors >(RGB) will no longer be apparent because all three colors are >slightly out of focus.
Before posting it here, I had sent the sample to Reikan suggesting it was a problem. They seemed to concur (I don't think they would mind my posting it). Here FWIW:
Thank you very much for your comprehensive information. It certainly looks like there could be an issue there. We specifically modified the analysis algorithm to try to avoid the effects of CA in FoCal 1.5, but there is one further step that we're look at for FoCal 1.6 which should allow us to identify the amount of CA present and adjust results appropriately.
It's good to see specific examples from you, and we'll be looking for this effect during testing (the Canon 85/1.2 shows this quite a lot).
At present, if you have FoCal Pro you can choose to stop FoCal changing the Exposure Compensation (which it sets to +1EV for the Fully Auto test), and ensure the camera is set to no exposure compensation. This can limit the effect of the CA to some extent and may change your results for the better.