Currently shooting with a 6D, I've been using the Tokina 11-16 f/2.8 lens which I'd bought for my old Rebel XSI which fortunately for me at 16mm there isn't any vignetting. It's a great lens for a crop sensor but now that I've moved to full-frame I'm feeling the need to step up to a proper lens specifically for my night sky shooting. I've heard really great things about both the Rokinon and the Canon L lenses in 24mm & f/1.4. Is one any better than the other for this type of work? Is there another one which I should be considering beyond these two?
Thanks in advance,