One of my favorite websites for photography education is the Digital Photography School! Most all the content below was taken from articles on their site. Direct links to the in-depth articles are posted below each section.
Understanding ISO, Aperture, and Shutter Speed
ISO – the measure of a digital camera sensor’s sensitivity to light
Aperture – the size of the opening in the lens when a picture is taken
Shutter Speed – the amount of time that the shutter is open
The Window Metaphor:
Imagine your camera is like a window with shutters that open and close.
Aperture is the size of the window. If it’s bigger more light gets through and the room is brighter.
Shutter Speed is the amount of time that the shutters of the window are open. The longer you leave them open the more that comes in.
Now imagine that you’re inside the room and are wearing sunglasses (hopefully this isn’t too much of a stretch). Your eyes become desensitized to the light that comes in (it’s like a low ISO).
There are a number of ways of increasing the amount of light in the room (or at least how much it seems that there is. You could increase the time that the shutters are open (decrease shutter speed), you could increase the size of the window (increase aperture) or you could take off your sunglasses (make the ISO larger).
Ok – it’s not the perfect illustration – but you get the idea.”
(Taken from: Learning Exposure in Digital Photography – For a more in-depth description check out the link)
Rule of Thirds
The basic principle behind the rule of thirds is to imagine breaking an image down into thirds (both horizontally and vertically) so that you have 9 parts.
With this grid in mind the ‘rule of thirds’ now identifies four important parts of the image that you should consider placing points of interest in as you frame your image.
Not only this – but it also gives you four ‘lines’ that are also useful positions for elements in your photo.
(Taken from: Rule of Thirds – For a more in-depth description check out the link)
At its simplest – the reason we adjust white balance is to get the colors in your images as accurate as possible.
You might have noticed when examining shots after taking them that at times images can come out with an orange, blue, yellow etc look to them – despite the fact that to the naked eye the scene looked quite normal. The reason for this is that images different sources of light have a different ‘color’ (or temperature) to them. Fluorescent lighting adds a bluish cast to photos whereas tungsten (incandescent/bulbs) lights add a yellowish tinge to photos.
The range in different temperatures ranges from the very cool light of blue sky through to the very warm light of a candle.
So for cooler (blue or green) light you’ll tell the camera to warm things up and in warm light you’ll tell it to cool down.
(Taken from: Introduction to White Balance – For a more in-depth description check out the link)