What does ISO mean in camera terms

caspa

caspa

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I've got a sony cyber shot 7.2mp, it has an option in the menu to change ISO settings from auto to, ISO 100, ISO 200.....up to ISO 1000.

What am i changing??? Light sensitivity??? Shutter Speed??

Anybody Know??
 
ISO is a measurement of a digital camera's imaging sensor's sensitivity. Digital cameras with high ISO capability are better able to take low-light images and pictures of fast moving objects.
 
Thanks, so for example ISO 1000 is more sensitive than ISO 100
 
Plain and simple - the term comes from film days where the higher the ISO the less light you need but the trade off comes in the form of grain.

As far as I'm aware things are similar for digital in so far as the higher the ISO the greater the sensor's sensitivity to light. http://en.wikipedia.org/wiki/ISO_5800:1987#Digital_camera_ISO_speed_and_exposure_index

IMHO always shoot in as low of an ISO as the conditions will allow.

BTW - there is a practical consideration as well - on my 400D if I shoot at an ISO of 1600 I can take approx 173 photos on my 2gb card. At 100 I can take 193. :)
 
You should always shoot at the lowest possible iso speed that your subject will allow for.

Higher iso = more noise especially on a higher megapixel smaller sensor camera. The more pixels they squeeze onto a given size the smaller the actual pixel size, the larger the signal to noise ratio, especially as the sensitivity of the pixels is increased by using a higher iso.

So in your case dont use the higher values unless you cannot get a shot a without it.
 
bwana said:
Plain and simple - the term comes from film days where the higher the ISO the less light you need but the trade off comes in the form of grain.

As far as I'm aware things are similar for digital in so far as the higher the ISO the greater the sensor's sensitivity to light. http://en.wikipedia.org/wiki/ISO_5800:1987#Digital_camera_ISO_speed_and_exposure_index

IMHO always shoot in as low of an ISO as the conditions will allow.

BTW - there is a practical consideration as well - on my 400D if I shoot at an ISO of 1600 I can take approx 173 photos on my 2gb card. At 100 I can take 193. :)
Click to expand...
The extra space is the noise that it introduced to the image at high ISO settings. Noise (being random) is very hard to compress.
 
arf9999 said:
The extra space is the noise that it introduced to the image at high ISO settings. Noise (being random) is very hard to compress.
Click to expand...
Makes sense. Thanks for the explanation. :)
 
Also ASA means the same thing, but is never used these days

ISO being International Standards Organization (IIRC)
ASA being American Standards Association.

Lower ISO means more quality but less sensitivity, higher ISO means less quality but sensitivity. Usually you'll only really start noticing noise from about 400+ on a decent camera.
 
hope a newer model dos'nt come out in two months time.
 
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