I don't know what my deal was, but I had a super hard time nailing focus on Baby A on these. Probably I was shooting too wide and too close, but even at 2.8 I had a hard time. And, I was shooting 1/125sec, which is higher than I do often (if the light's just not there I often shoot at 1/100 or even 1/80) The back eye was consistently soft..grr. Maybe it was just one of those days. He is always harder to get sharp focus than D, though.