Here's an example of the narrow depth of field you can get with this shot, taken wide open. The lighting is a bit weird, with natural shaded light coming thru the window, and incandescent lighting from the rear.
Kawai takes this position when we come or go normally, but for full disclosure, I should reveal that this shot was staged. I asked him to look out the window, and he did just long enough for me to get a couple shots.
I intended to focus on the eye/muzzle, but missed focus just a little (focus point is in front of my target). An electronic viewfinder (EVF) is always much more useful than an optical viewfinder when trying to use lenses with wide apertures wide open. Stopping down two or three clicks, the eyes would have been in focus too.
All remaining photos were taken at f/2.8, which is one click down from wide open.