Originally posted by Docrwm Thanks for that link. Another +1 to you for that resource.
it is useful to get an idea of how lenses perform (or focal lengths. even across various formats - I really like this site myself
For example a 40 mm at 10 feet f2.8
on apsc
Depth of field
Near limit 9.04 ft
Far limit 11.2 ft
Total 2.15 ft
In front of subject 0.96 ft (45%)
Behind subject 1.19 ft (55%)
Hyperfocal distance 92.9 ft
Circle of confusion 0.02 mm
on FF or 35mm
Depth of field
Near limit 8.83 ft
Far limit 11.5 ft
Total 2.71 ft
In front of subject 1.17 ft (43%)
Behind subject 1.53 ft (57%)
Hyperfocal distance 74.4 ft
Circle of confusion 0.025 mm
on 645 MF
Depth of field
Near limit 8.07 ft
Far limit 13.1 ft
Total 5.08 ft
In front of subject 1.93 ft (38%)
Behind subject 3.15 ft (62%)
Hyperfocal distance 41.4 ft
Circle of confusion 0.045 mm
on 6x7
Depth of field
Near limit 7.58 ft
Far limit 14.7 ft
Total 7.1 ft
In front of subject 2.42 ft (34%)
Behind subject 4.69 ft (66%)
Hyperfocal distance 31.1 ft
Circle of confusion 0.06 mm
So in this case you'll get better bokeh (morr OOF areas from APSC then the other formats
so much for the FF arguement