DSLR cameras, the big bulky Nikon and Canon cameras you see photographers and your cousin Mimi rocking at weddings, aren't going to go away any time soon, but mirrorless cameras, like the excellent Sony A9, have gotten good enough to make the Nikons and Canons of the world scared. So Nikon's latest full frame professional camera, the D850, borrows some pro experiences from it's mirrorless rivals: Including a tilting display, focus stacking, and mirror-free shooting.