再瞎算

用300 MM 在D300 照12 MB 像當於 450 MM WITH 12 MB RESOLUTION。
[D300: 12 MB， 300mm on D300 = 300 mmx1.5 = 450 mm in 12 MB resolution.]


用300 MM 在D800 照全副，再裁小到 12 MB 像當於 900 MM WITH 12 MB RESOLUTION。


[D800: 36 MB, 300mm on D800 = 300 mm in 36 MB resolution, crop to 12 MB
=300 mm X 3 = 900 mm on 12 MB resolution. ( however sensor area/pixcel 
on

D800 is smaller than D300 by 0.774 倍).]

900 mm/450 mm = 2.0 in 12 MB base.