ISO questions

[Ilovemycam]

Why did they come up with ISO to replace ASA?

Is ISO = to ASA?

Is ISO standardized with every cam company? Or is one cams 6000 ISO offer more sensitivity than anotherr cam companies 6000?

 

[Ysarex87 81]

Yes ISO = ASA.

ISO is International Standards Org.
ASA is American Standard Assoc.

Yes it is standardized across camera companies. As for the reason to change -- International is more inclusive.

Joe

 

[KmH]

The American Standards Association (ASA) is now the American National Standards Institute (ANSI) American National Standards Institute - Wikipedia, the free encyclopedia.

One of the benefits to doing Internet searches is, usually discovering information you didn't know you would want to know.
If you don't do any Internet searches, you miss out on making those discoveries.

Film speed - Wikipedia, the free encyclopedia
International Organization for Standardization - Wikipedia, the free encyclopedia

 

[christop]

Heh... ISO. It's one of those non-acronyms that looks like an acronym.

UTC is similar; it's actually an out-of-order acronym in both English (Coordinated Universal Time) and French (Temps Universel Coordonné).

The stuff you can learn on the Internet.

 

[Derrel]

If you don't do any Internet searches, you miss out on making those discoveries.

I looked all over the internet KmH...and all I found were Hot Russian Singles! and Sexy Single Moms! and Secret Car Insurance Trick Insurance Companies Don't Want You To Know About!

I supposed it was because ISO is personals-speak for In Search Of.... as in single white male ISO hot Russian single mom for purely platonic photo sessions...

 

[Helen B]

Why? To produce an international standard while maintaining the two most common speed rating methods.

To fill in some details:

There were two common film speed standards in the west: ASA and DIN. The ISO technical committee responsible for film speeds (which happens to be lead by ANSI, the successor to the ASA) combined them, continuing both. Nowadays you can use either an ISO speed that is the same as ASA film speed, or an ISO speed that is the equivalent of the DIN film speed. The former is arithmetic (double the speed, double the number) and the latter is logarithmic (double the speed and add three to the number). The logarithmic version is distinguished by being followed by the degree symbol, eg 21° although the number values themselves usually tell you which version is being used.

The manufacturers have a lot more wiggle room with the ISO for digital cameras than they do with film. They are all stated to a fixed set of numbers that are a third of a stop apart, so there is no such thing as ISO 110, for example.

Apart from digital, there are standards for B&W silver-image negative film, colour negative film, and colour reversal film, all for still camera use. All other types of film, including motion picture film, cannot really quote an ISO speed - they have to use an EI (Exposure Index) which is a manufacturer's recommendation rather than a standardized speed. Numerically it equals ISO.