I had two Carl Zeiss lenses with separation: a Sonnar 50/1.5 in Contax rangefinder mount and a 150/4 for the Hasselblad. The separation was very bad: distinct "rainbows" that started at the lens outside and ended half-way towards the middle. Dealers and friends alike asked me why on earth would I use such lenses. I emailed a photo of the Sonnar 50/1.5 to Henry Scherer who said something like it was one of the worst cases of separation he'd seen.

However both performed fantastically, in black and white and color, pointed into the sun or away from it. I never noticed any effects at all. People couldn't believe it. I suppose Your Mileage May Vary.