hoTTub

Higher is more light or less light?

o2bnme

So, the higher the number, the faster the shutter can be because less light is needed to activate the film 'sensor'

Typically, 100-400 is a good number. 400-1600 gets more noise on the film or image.

You'll get the best quality with an ISO like 64 or 100. Since you are probably talking about a digital camera, that would limit you to 100.

OTOF

The best meaning of ISO is Incentive Stock Option, lol, or mod money..okay, I'm working on the pics!

gtt

yes come on....we're waiting ;-)

KimTT

What is ISO?
ISO is the abbreviation for the International Standards Organization, an agency that specifies many standards, not just photographic ones. Their standard, ISO 5800:1987, specifies how to measure the film speed for color negative film.

RTinNYC(again)

This should sate even your lust (for knowledge)... :-p<ul><li><a href="http://www.howstuffworks.com/film2.htm">From howstuffworks.com</a></li></ul>

ZGTT

I like to watch!!!! (pictures?)

Don

Each doubling of the ISO (which used to be ASA) is the same as increasing the aperature by 1 f-stop, or doubling the exposure time. So if the exposure for ISO 100 film is 1/125 @ f 16, by using ISO 200 film you could either expose at 1/250 @ f 16 or 1/125 at f 22. If you don't understand that, that's ok, just go with the "more activated" explanation! It is true that the trade off is that with higher ISO, with film you'll get more visible grain, and with digital more noise.

voughtt

A film with an ISO or E.I. (exposure index) of 100 needs twice as much exposure for a given scene as an ISO 200 film.

So, to answer your question, higher numbers need 'less light'. Films with higher E.I. tend to have more noticeable 'grain'.

Digital cameras often have 'ISO' settings which work much like the analog equivalent. Each doubling of the ISO number increases the sensitivity of the sensor by a factor of 2, but also increases the amount of random noise.