Had the 85 L II. It’s not that slow. It’s slower than other L lenses yes but it’s also a portrait lens mostly and there is just so much glass to move in it. Awesome lens. But yes no good for a “walk around”. That thing on a 1Diii was enough to give you scoliosis.
Haha, I had two across my photography hobbying - for their intended purpose they're impressive, but realistically a worthless investment outside of anything other than shooting at f/1.2 to f/2.0. Still easier to use than the bubble-fronted 17mm TS-E L though!
Small point on mirrorless though (I didn't have time to comment earlier in the day) - lenses are no smaller with mirrorless than with D-SLRs for the same size aperture and sensor size. The distance from the aperture to the sensor (or film) still has to be the same distance apart and it still has to cover the sensor. The shorter distance from the sensor to lens mount flange on most mirrorless cameras can actually mean all the lenses that attach make up the extra distance which can make for a small camera and a bunch of big lenses. If a lens is smaller for the same focal range and aperture, it means it projects a smaller image circle over the sensor/film. It's good for making lenses more compact and allowing room for autofocus, but often leads to weaker performance in the corners of the image. There's a reason the optically best lenses are huge and often lack AF - oversized image circle, and the sensor doesn't dip the corners into the far reaches of the image circle. Most mirrorless cameras have smaller lenses because the sensors are APS-C of Micro 4/3rds.
Prime lens can be surprisingly compact for the aperture and focal length, but a bag full of primes isn't small/light either!
And
@leitch - I had a a7rII and
hated the EVF. I found a D-SLR OVF much easier to live with when trying to shoot anyrhing moving (especially once I converted the focus screen in my 5D III to a ground glass unit that actually showed the true focal plane at wide-open aperture). Also whoever layed out the menus (or didn't) on the Sony a7/r/s cameras deserves bamboo under the fingernails for the rest of their mortal existence. Such a shit system to use (but oh what a sensor!).
[EDIT] Yes, I'm a tech nerd about many things.