Hello,
On Sat, 1 Dec 2001, Andy Schmitt wrote:
(sorry Europe but there really is a use for inches)
I doubt it ;-) Since the method you used was based on fractions, it does
not matter at all which units you use. So no excuses for not using
metric! ;-)
Regards,
Robert
There is no rule of thumb, just plain physics of light.
This case is in no way different than if you were using a glass lens.
I guess you could say the rule of thumb is to add 2 stops every time you
double the focal lenngth.
You can think of it this way... If you have a 50mm lens at f/16,
That was my instinct, Guillermo, and thanks for your
answer.
Funny thing is, I tried it yesterday at a minute and a
half--my rough calculation, which was close to your
suggested 84.5 seconds--and it completely overexposed
the film. It was all white (using Polaroid Type 55).
Then I tried it
