[davidmanze]

Blurb aside, my question was why Mark Smith doesn't tell us anything negative about shutter lag?

My next question will be which are your personal experiences with that Sony? Why should we care about shutter lag with exotically long FL? And which DSLR will focus accurately at 1200/8? Who cares about small shutter lag if the picture is out of focus? How often did you shoot with 1200/8? Or more likely with 1200/12.6 because that's what your current Tamron delivers.

Why should we care about 120 Hz refresh rate, if it remains uncertain what the refresh rate has to do with shutter lag?

What, besides another typical YouTube "issue", is the real world significance?

I follow his videos, they're very good !

..... it's not the shutter lag .... but the refresh rate. (1200mm)
 You get a new EVF image every 1/120 sec. ..... so effectively you hang on to the same image until the next update 1/120 th sec. later ...... meanwhile the birds moved on without being able to see it advance in the viewfinder.

Mark probably has no need of those longer focal lengths he's always near to them.