I think Darwin and Heisenburg teamed up on this lens...
Maybe I fell victim to Natural Selection when I bought this on EBay... I wonder if many used lenses there are being sold because they are not good copies.
My copy captures exotic light at 1.4 especially in low light where it exhibits apparent sharpness. But when I try to get sharp photos in bright light nothing I do helps. F8 you ask? Nope... Hood and front lighting with a totally staged shot? Nope... After hours of trying, luckily the sun will begin to set and then you can coax out a jaw dropper. The closer you try to replicate its low light performance in daylight the farther you will get from it.
I've heard reports the lens design physically precludes sharpness after 1.4. I havent disproven this. Of course at 1.4 the depth of focus is so shallow its easy to blame things on that, while the background is excused by depth of filed limitations.
Yeah I know I should send it in for calibration but its a professional lens and I am just being stubborn I guess. Besides, my experiences are too similar others to go through the expense and hassle.
So now it is a niche lens for me. I had hoped it would be my "one lens" holy grail but have resigned myself to wander the earth in search of a sharp Canon "wider than 35L" walkaround prime.
Will I buy the 24 1.4L II ? Sharper probably, but come on now Canon... you made your bones by not overcharging like Nikon, dont leave us believers in the dust.