Hi All:
This is off topic, but of possible interest to the group.
Several years ago I photographed a night missile launch from my old photo
site 100 miles from the launch pad with ASA 100 film at f/2.8. The exposure
was more or less perfect.
I want to photograph the exact same type of launch at night, but from a new
photo site that is half the the distance from the pad. Assuming I apply the
inverse square law correctly, I get the following exposure data:
Old Site New Site
-------- --------
Distance: 100 miles 50 miles
Film ASA: 100 100
Exposure*: 200 sec. 200 sec.
f/stop: 2.8 5.6?
Is my assumption correct that the point of light from the missile's first
stage is four times brighter from half the distance?
Regards,
Brian Webb
* The exposure has to be of a fixed duration in order to make a nice time
exposure
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