So yeah, this is as bad as it gets, sun high in the sky,blue bird, white reflective transperent cup, reflective background. Everything in this pic produce CA. This would be one of those times you should stop down to get rid of the CA , but who can resist the f0.95 right? :).
It took a couple of minutes to correct most of the purple CA in Photoshop, 1st pic is a corrected version and the 2nd is a 100% crop.
3rd pic is a non corrected and the 4th is a 100% crop of that one.
I usually dont bother/care about CA but in this case it totaly ruined the picture, and its not that big of a deal to correct when it gets bad.
mostly all i need to do (in my opinion) is decrease the saturation of purple in Lightroom and the worst is gone, and when it all turns to shit, i´ll use PS for a couple of minutes.
If you dont know how, just check Youtube.
All shot with Em5 and Nokton 42.5mm f0.95 @f0.95 with B+W ND4 iso200 1/4000