Andrew,
Although the light this morning was reasonable, the group shot of the Herons and BFS is just over 200 metres away (checked on google earth) and consequently there must be some build up of pollution particles.
Whereas the close up shot of the BFS was about 20 Feet away and the bird came closer but I ran out of focus ( minimum focus of the scope is 16.5 feet.)
Regarding the scanner I suggest you send KK Hui a personal message as I remember he used to have a Nikon scanner. Also remember that the pollution has become a lot worse of the past couple of years, your film images may have been taken in "the good old days"
Bob Thompson