Digicam's ISO setting

Can anybody give me a brief explanation on to how to choose the ISO setting of a digicam to suit a particular situation generally? Say in the daytime and nitghttime. All the stuff that I've read mostly explain on film grain rather than on digicam's setting and application. It would be most helpful you could gimme some recommendations to sites with explantion to this topic. Thanks.

[Zerstorer]

Basically, raise the ISO rating when you are unable to get a sufficient shutter speed for a sharp even at max aperture under the prevailing conditions.

Its the same as film, use a high ISO film when u need to shoot in low light and/or require faster shutter speeds.

[cafe vienna]

Hi there,
The ISO setting works in the same way as you would load in a film of different ISO settings. Generally, ISO100 is for places with lots of lights and generally ISO400 is for night time shots.

In terms of ISO for digicam, the ISO is emulated on the shots. Generally, the higer the ISO the grainer is the "film" so you can understand why the stuff you've read all allude to that. So in an "emulated" format, the ISO on a digicam works in the way where the higher the ISO, more "noise" can be seen in the digital photographs. I hope this helps

Originally Posted by Snappy Can anybody give me a brief explanation on to how to choose the ISO setting of a digicam to suit a particular situation generally? Say in the daytime and nitghttime. All the stuff that I've read mostly explain on film grain rather than on digicam's setting and application. It would be most helpful you could gimme some recommendations to sites with explantion to this topic. Thanks.

[AReality]

ISO on a digital camera is the amplification of the amount of light received.
a photo taken at ISO100, 1/30s
has the same exposure as at ISO200, 1/60s
also the same at ISO400, 1/120s
*note: ISO doubles, & shutter speed faster by 2x also.

The difference is the noise level on the photo. ISO100 has less noise than ISO400.


for night scenery, if U have a tripod, U can use lower ISO (ISO100?) to reduce the noise. if no tripod, then U'll have to use a higher ISO so that U can use a faster shutter speed.

For sports,
for example, if you need a minimum of 1/250s to freeze the action, and your camera says that at ISO100, you need 1/125s to have the correct exposure,
then U'll have to compensate by changing the ISO to 200, thus getting 1/250s. Disadvantage is there's more noise.


it a goes down to whether the shutter speed is acceptable to you or not.

(Ignoring the use of aperature here... assume aperature remains the same.)