Well I tried this new 'Face Detection
Zoom' yesterday with Mrs Banner
The technique worked a treat!
Using the K-1+FA77 and Ringbox for flash, I was in Live View mode using Face Detection, as soon as I got the yellow box confirmation for the face I focused in and got a lock, I then used the 'OK' button which gave me an ultra quick zoom to the eyes. Now... because I was using the Ringbox flash and the FA77 doesn't have Quick Shift focus, I opted instead to just physically move my camera slightly further or closer away from the subject whilst keeping an eye on the Live View screen and analysing the level of clarity and sharpness I was seeing on the eye (and lashes). Once I felt I had it as sharp as I could get it I took the shot. This was the result below;
This was taken at f2. As you can see (ring flash personal taste aside) her left eye is perfectly sharp, lashes included. Shooting f2 this close (this is an uncropped shot) makes it very hard to land that kind of eye focus well, very thin DoF, so much that her other eye is very soft.
NB: If you are also shooting more stopped down, during the time when you have pressed the 'OK' button and have a zoom in on the eyes, if you also activate the optical/digital preview slider switch (the same switch for on/off) you get to see the shot as it would appear if taken, handy for even greater clarity focus feedback.