We are faced with two moments of selection and thus of possible regret: the first and more serious when actuality is there, staring us in the viewfinder; and the second when all the shots have been developed and printed and we have to reject the less effective ones. It is then – too late – that we see exactly where we have failed. When we are at work, a moment’s hesitation or physical separation from the event robs us of some detail; all too often we have let our eye wander, we have lost our concentration; that is enough.