When to use iso/apeture

Hello and happy easter to all i was just wondering when to use the iso settings on my S50 camera in stead of leaving it in the auto mode all the time.What do i look for to know when to use that setting also the same with the apeture feature also PLEASE help.

With the ISO-setting you can change the sensitivity of your sensor, and the effect is that the camera will use a faster speed or smaller aperture. The downside is that a higher ISO will cause more 'noise' in the picture, like the grain in the film days.
So I always use ISO 50 instead of Auto just to prevent the 'noise'.

The exposure of a picture is made by a combination of shutter speed and aperture; if you use a shorter speed you need a bigger aperture and the other way around. You use a shorter speed to freeze moving objects and a longer speed just to create the idea of something moving, like a car with a blurry background.
On the other hand a bigger aperture ( a lower number ) will result in less DOF (Depth of Field) and a smaller aperture (a higher number) will give you more DOF. So when you want a portrait with an unsharp background you will use aperture 2 and for a picture of a landscape you'll use 8.

I hope this will help .

If you are shooting in low light then a higher ISO setting will enable you to have a higher shutter speed for the same size aperture. Noise on the picture is always better than camera shake. IMO.
So I usually change the ISO setting depending on the lighting conditions. But I also tend to use ISO 50 most of the time.