I haven\'t experienced such flare, but I always use the hood, which may help. I suspect, however, that I just have never shot into strong enough light. Pretty much any lens will show diminished contrast shot into bright light and I doubt the 100 MP is an exception.
I got flare even when using the hood, especially wide opened, but it doesn\'t always happen, maybe depending on the angle? I always got clear, high contrast image with the Zeiss 21mm even shooting directly to the sun.