last friday, some of us were shooting star trial next @ punggol mrt (no foreground because too bright, was thinking of including the lone bunglow at 1st).
I get a 40mm star trail with 320mm lens (100mm+2xtc+1.6xcrop on D60) for 5min when print 4R size
As rule of thumb, everytime we 1/2 the focal length, the area of coverage increase 4x.
So to get 40mm star trail with 150mm lens, 5min x 4 = 20min
40mm star trail with 75mm lens, 20min x 4 = 80min.
40mm star trail with 35mm lens, 80min x 4 = 320min.
Pls advice is a/m assumption is correct. Thanks.