ISO equivalent

Can anyone please tell me how ISO values relate to either DIN or ASA
film speed?

Thanks

--
"When fascism comes to America, it will be wrapped in the flag and
carrying a cross."
Sinclair Lewis

On Thu, 22 Mar 2007 14:57:09 -0700, Ockham's Razor
wrote:

Can anyone please tell me how ISO values relate to either DIN or ASA
film speed?

The numbers commonly used on digital cameras (eg "ISO 100")
are the same numbers used in the old ASA scale.

But film has also used ISO for many years, perhaps you
haven't noticed ;-)

--
John Bean

In article
, Ockham's
Razor wrote:

Can anyone please tell me how ISO values relate to either DIN or ASA
film speed?

Thanks

Such things as these are easily searched for using google.

Googled, from LuminousLandscape.com:
A) The technical answer is that no digital camera has any true ISO
speed: there is only an ISO standard defining film speed, based on
things like shadow handling and contrast, and this is reported in both
ASA Exposure Index units like 100, 125, 160, etc. and DIN degree units
21º, 22º, 23º, etc. (Note that films always report the speed as
something like "ISO 100/21º", combining the ASA and DIN units. Despite
what numerous photographic books say, it is not true that the ISO
standard simply adopted the ASA scale: they merged ASA and DIN, for the
sake of international bureaucratic harmony.)

There is no such ISO standard for the sensitivity of electronic sensors
yet. (There is a "base ISO" standard for the overexposure limit of a
sensor, but that is the opposite thing to a sensitivity measure.)

B) The practical answer is that almost everyone (incorrectly?) refers
to those ASA units for measuring Exposure Index by the name "ISO",
regardless of whether a high "ISO" setting has far better or worse
shadow handling than required of a film with that ISO speed rating.


More from wikipedia:

ISO film speed scales

The standard known as ISO 5800:1987 from the International Organization
for Standardization (ISO) defines both a linear scale and a logarithmic
scale for measuring film speed.

In the ISO linear scale, which corresponds to the older ASA scale,
doubling the speed of a film (that is, halving the amount of light that
is necessary to expose the film) implies doubling the numeric value
that designates the film speed. In the ISO logarithmic scale, which
corresponds to the older DIN scale, doubling the speed of a film
implies adding 3° to the numeric value that designates the film speed.
For example, a film rated ISO 200/24° is twice as sensitive as a film
rated ISO 100/21°.

Commonly, the logarithmic (DIN) component is omitted from film speed
ratings, and only the linear component is given (e.g. "ISO 100"). In
such cases, the quoted "ISO" rating is in effect synonymous with the
older ASA standard.

--
You need only reflect that one of the best ways to get yourself a
reputation as a dangerous citizen these days is to go about repeating
the very phrases which our founding fathers used in the struggle for
independence.
-- Charles A. Beard

Can anyone please tell me how ISO values relate to either DIN or ASA
film speed?

15 DIN = ISO 25
....
18 DIN = ISO 50
19 DIN = ISO 64
20 DIN = ISO 80
21 DIN = ISO 100
....
24 DIN = ISO 200
27 DIN = ISO 400

etc, every 3 DIN the ISO is doubled. Or every 1 DIN, ISO is x1,26

DIN is logarithmic scale. ISO is linear
--
Dimitris M

Dimitris M wrote:
Can anyone please tell me how ISO values relate to either DIN or ASA
film speed?

15 DIN = ISO 25
...
18 DIN = ISO 50
19 DIN = ISO 64
20 DIN = ISO 80
21 DIN = ISO 100
...
24 DIN = ISO 200
Morton
27 DIN = ISO 400

etc, every 3 DIN the ISO is doubled. Or every 1 DIN, ISO is x1,26

DIN is logarithmic scale. ISO is linear
You can just remember that 12 DIN = 12 ISO, and that adding 3 to the DIN
= doubling the ISO.

Dimitris M wrote:
Can anyone please tell me how ISO values relate to either DIN or ASA
film speed?

15 DIN = ISO 25
...
18 DIN = ISO 50
19 DIN = ISO 64
20 DIN = ISO 80
21 DIN = ISO 100
...
24 DIN = ISO 200
27 DIN = ISO 400

etc, every 3 DIN the ISO is doubled. Or every 1 DIN, ISO is x1,26

DIN is logarithmic scale. ISO is linear

So if a company is ISO 9000 certified, it works in extremely low light?

"Cynicor" wrote:

So if a company is ISO 9000 certified, it works in extremely low light?

Merely that it's a division of Nocturnal Aviation.
http://www.dpbsmith.com/applegunkies...3divisions.mp3

And don't forget Apply Gunkies, rhomboidal pellets of true fruit flavor.
Dunk a Gunk Today!
http://www.dpbsmith.com/applegunkies/mp3/ag01.mp3

David J. Littleboy
Tokyo, Japan

Cynicor writes:

Dimitris M wrote:
Can anyone please tell me how ISO values relate to either DIN or ASA
film speed?
15 DIN = ISO 25
...
18 DIN = ISO 50
19 DIN = ISO 64
20 DIN = ISO 80
21 DIN = ISO 100
...
24 DIN = ISO 200
27 DIN = ISO 400
etc, every 3 DIN the ISO is doubled. Or every 1 DIN, ISO is x1,26
DIN is logarithmic scale. ISO is linear

So if a company is ISO 9000 certified, it works in extremely low light?

Yes, certification is a shady business.

--
Måns Rullgård

Cynicor wrote:

So if a company is ISO 9000 certified, it works in extremely low light?

Does seem that way sometimes, in my experience. Maybe "in the dark" is
the right phrase, as in "it seems like they're working in the dark".

David Dyer-Bennet wrote:
Cynicor wrote:

So if a company is ISO 9000 certified, it works in extremely low
light?

Does seem that way sometimes, in my experience. Maybe "in the dark"
is the right phrase, as in "it seems like they're working in the
dark".

So ISO 9000 is the official standard for mushroom management? "Keep 'em
in the dark and feed 'em, uh, manure"?

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)