by Peter Irwin <pirwin@[EMAIL PROTECTED]
>
Nov 1, 2007 at 12:00 AM
UC <uraniumcommittee@[EMAIL PROTECTED]
> wrote:
>
> It is my opinion, and that of many others, that the 'new' ASA speed
> sytem introduced in 1959 gives numbers that are too high, by about 2/3
> stop.
I think the primary reason for this is that the question
you want the ISO rating to answer is a different question
from the one it was designed to answer.
The question the speed rating is designed to answer
is "what is the minimum exposure required to produce
a negative from which a print judged to be 'excellent'
can be made?"
The question you probably want answered may be
something like "What exposure meter setting will
consistently give negatives that are easy to print
well?"
The answer to the second question is going to generally
be a lower exposure index than the ISO standard.
Peter.
--
pirwin@[EMAIL PROTECTED]
