Wow, I haven't had my C-Biogon flare like this at all...
And what's this all about? This is like attempting to find who farted at the Special Olympics, catching fairies by the wings, and counting angels on pin heads.
Flare is the luck of the draw, NEVER a legitimate consideration in choosing a lens to purchase and a complete denial that there are basic rules of photography.
Rule No.1: Always keep the sun behind you and over your shoulder
Rule No.2: Always fill the frame
Rule No.3: Always focus 1/3 in 2/3 out
Rule No.4: Always shoot to the slowest speed necessary make a capture
!