Hi,
Glad that helped... Now to get a good picture, if you have a dim scene, to get a good picture, you'll need to get enough light into the camera to capture it, and keep the camera steady while you do.
To get more light into the camera, the two settings I mentioned before, f-stop and exposure time, control that.
F-stop is the measure of how open the aperature (the adjustable 'hole' that the light passes through on it's way to your camera's ccd) is. Lower numbers mean that the opening is larger, on my camera f2.0 if the largest opening, larger numbers (such as f8.0) means that the iris is closed more. The f-stop setting impacts other aspects of picture taking as well; such as the depth of field, the range of distances from the camera in which items are in focus. Though for most digitial camera's, the depth of field is so large, that this isn't much of a concern.
And for exposure time, this is probably more obvious... the longer the shutter is open, the more light will get to the sensor.
These two settings work hand in hand, for a scene to shoot, you'll generally find that if you have a working combination of the two... say f2.8 and 0.4 seconds, that you can get a good shot with another combination... say f8.0 and 1.0 seconds. Closing the aperature (high f-stop) needs more light, hence longer exposure (1.0 seconds).
So back to your specific case... for shooting low light, a low f-stop (f2.0 or f2.8) will have a wide open aperature, and less exposure time needed, and less chance of introducing shake if you're holding the camera. If your camera has an Aperature Priority Mode as one of the manual settings (my Canon S40 labels it as "Av" on the dial, I believe that's somewhat standard), selecting that will allow you to select the aperature setting, and the camera will decide the exposure time, That may help you in low light settings if the camera is deciding that it want's a higher f-stop, hence requiring longer exposure times.
Now keep in mind, that you will get difference pictures with different combinations of settings, even if both are relatively equally exposed. I don't know what you're trying to shoot in low-light, but I find that for the pictures I like to take, I generally prefer closing the aperature down (to f8.0) and taking the longer duration shots. As an example of this, when shooting fireworks, I've found that if I go with a wide open aperature (and shorter exposure time) I tend to get more pictures of smoke, while if I close the aperature and take the longer duration exposure, get better shots of the fireworks. A closed aperature also tends to introduce the starlight effects around lights, and increases the depth of field so that items both near and far are more sharply in focus.
Hope this helps... best advice is to experiment and take lots of shots... if you're not sure, shoot several with various settings and see if you get something you like.
Good luck,
Bernie
