Moose writes:
>Man, I hope that's not me! However, Ctein happens to have opined on
the subject
>in what I find to be useful ways today
>on TOP.
><http://theonlinephotographer.typepad.com/the_online_photographer/2012/0
9/why-iso-isnt-iso.html>
> Perhaps he will
>convince you that there is no "true" ISO. :-)
It has been my understanding that Dr. ISO is indeed a member of the
Moose collective along with Dr. Noflash.
I should have attempted to be more concise with terms in this confusing
area. Not only is the ISO concept fuzzy with dig snesors but the "cam
ISO" used by it may differ from the dial setting---that is where CHDK
comes in. The fuzzy is now even fuzzier. It seems the best intuitive
measure may be the SOS method and if there were a cross manufacturer
effort , ther could indeed by sort of a standard. As that is typically
using a JPEG; however it might hamper the engineers as to how to
optmally apply tone curves for their sensor and thus not a good idea
afterall. I think AG is spot one with slide film though as there is a
clear mid-tone standard.
John Shaw even recommended calibrating his ext meter using the slides
themselves.
I also now wonder how usefaul a new fancy Sekonic meter actually is for
digital. Reading the last "rawdigger" site and others it seems it might
have to be callibrated as to what is best for the
particular cam and indeed may not apply to all lighting conditions with
different color temp.
harumph--haven't replaced my defunct meter --yet. Haven't shot slide
film since early Spring and hope I would't flub it up badly now.
A live 3 channel raw histo would render the ISO relatively moot
except perhaps for flash.
Background:
http://en.wikipedia.org/wiki/ISO_speed
DXO's method:
http://www.dxomark.com/index.php/en.../About/In-depth-measurements/DxOMark-testing-protocols/ISO-sensitivity
Calibrating exposure with dig :
http://www.rawdigger.com/houtouse/lightmeter-calibration
Exp meter callibration:
http://en.wikipedia.org/wiki/Light_meter
Mike
--
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/
|