What The Fudge Does ISO Do?

Joosh · What The Fudge Does ISO Do?

On my compact, there are 5 ISO settings and i was wondering if someone could help me as to what they did

Auto - im guessing fairly self explanatory
50
100
200
400

they have always been there and i have played but i dunno what they do...

thanks,

Joosh

duncan_g

My small knowledge is that if the ISO is low it is best for bright daylight type things. And a high ISO is best for darker, but it will be grainy.

Joosh

ok, but what does it actually alter?

i mean i would rather understand what it did and then use it than just know that its good for daylight/nighttime

not a dig btw

Joosh

Henry

Its started with how sensitive the film was, you can buy different grades of film, and it has translated into how sensitive the sensor is on digital cameras.

Joosh

ah ok, so is it kind of the higher the number the more light the film absorbs?

Joosh

Henry

No the quicker it absorbs it. I normally leave my ISO on 200 for day to day, and always use 200ASA(like ISO) film.

Joosh

ah ok i will play about

thankyou all

Joosh

dandantheadminman

yeh, most of the time, whooting biking (in the forest) I have it on 200 cause trees block out some of the light,

it depends on the camera as to what iso you can get away with without it getting too grainy.

Roo

Yeah, as explained above, ISO/ASA is just an international standard number to show the speed of a film, or the equivalent sensitivity of a digital sensor.

50iso is not very sensitive, therefore you need a larger aperture or slower shutter speed, 3200iso is very fast so you take take pictures with a fast shutter speed even in low light, but the faster the ISO, the more grain/noise you will see (the multicoloured dots in coulour pictures)

fozzybear

ISO is the rating assigned to how sensitive the sensor is to light..

the higher the iso the more sensitive the sensor is to light, the higer the iso the more "noise" is produced during the process of taking the photo... if you want an explination of why and how post again and i can dig out a full scientific explination.

Hamish

As the others have said the ISO is basically the film sensitivity.

The exposure (i.e. amount of light needed to get a photo looking correct and not too bright or dark) depends on only 3 things - aperture, shutter speed and ISO. I could explain it all but it'd take ages and I cant be bothered. I'd suggest that you look up a tutorial on exposure and it'll explain it all.

this might be a bit much but it'll give you an understanding:

http://www.luminous-landscape.com...g-series/understandexposure.shtml

dandantheadminman

nice link Hamish, thnx for that