Yeah that's the info I was looking for. I'm trying to figure out what the different camera settings mean. The camera guide tells me WHERE the adjustments are, but not WHAT they mean.
Ok, here's Stuart's Patented Five Minute Guide to Photograph Exposures.
There are four variables that affect exposure of a shot: ISO speed, aperture, shutter speed, and the actual amount of light. You have full control over three of those, and limited control over the fourth. Basically, if one of them changes, another one (or possibly all three) of the others have to change to compensate.
ISO speed: measures the sensitivity of the sensor (or film for 35mm cameras) to light. Think of old black and white film, which used silver compounds to form the image. The larger the clumps of these silver compounds, the faster they'd react to light, and hence the more sensitive the film (and the higher the ISO speed). Against this, you'd lose detail: the smaller the clumps, the more detail the film could capture. This still holds true today: the higher the ISO speed you set the sensor to in a digital camera, the more noise the camera will put in the image.
Aperture: the size of the hole letting in the light. It's expressed as a ratio: f/2 means the diameter of the aperture is the focal length (f) divided by two (/2). The wider the aperture (and hence the smaller the f stop), the more light you let in. There's a trade off, though: the depth of field (the thickness of the in-focus plane) decreases as the aperture gets wider. Handwave, handwave.
Shutter speed: how long the camera exposes the sensor or film to light. Obviously, the longer it is, the more light gets in. If you want to freeze action in your shot, you need a fast shutter speed, which means the aperture needs to be wider, the ISO speed higher, and/or the ambient light brighter.
Ambient light: you can affect this in two ways. A flash will give you more light for the exposure, but has limited range; there's not much use trying to use a flash on buildings a couple of kilometres away, for example. You can also cut down the light (useful if, for example, you want a shallow depth of field in bright sunlight) by using a neutral density filter - these absorb some fraction of the incoming light, but don't affect its colour. Circular polarisers are also very useful in many situations, especially outside in bright sunlight; they help to bring out the colour of the sky, for example - but they also reduce the amount of incoming light.
Wiki has articles on the three main ones above (aperture, shutter speed, and ISO speed) - they make a good place to start for more info. Play around, and you'll start to get a feel for it. Note that sometimes, depth of field is more subtle than the camera might indicate - eg,
this shot has a very shallow depth of field (it was taken at f/1.8 with a 50mm lens, fairly close), but more of the shot seemed to be in focus through the viewfinder than was actually the case. As I said: experimentation is the best way to understand all this.
