photo technicals- some basic geekery

wrote something for Work. it might be helpful for anyone who's asked me anything about photography (like you, uncle!)
this is not edited, and is part of a larger course-planning document for a photo workshop. if you're interested, read. if you're not, go admire some jiling poetry or photography, instead. by all means, do enjoy yourself. :)
Draw a diagram. Explain that the camera works just like the human eye… basically, you press the shutter release (camera button). Before you press the shutter release, the shutter (the camera "eye") is closed. When you press the shutter release, the camera eye opens, then closes again. During the opening and closing process, light is allowed into the lens (camera eye). Behind the camera eye, there is a detection mechanism. On film cameras, it's the film, which is sensitive to light. On digital cameras, it's a technical mechanism which is also sensitive to light, and translates into pixels. The more sensitive the detection mechanism, the greater the "ISO" of the film, or the higher the number of the ISO. (this number ranges usually from 80 to 1600). How quickly the camera eye opens and closes is called the "shutter speed." This ranges from holding the shutter down for as long as you want on some cameras (infinite time), to as quick as 1/6000 of a second. The shutter speed varies according to your camera and what lens you are using. The kids most likely won't need to know about shutter speed/ aperture/ ISO/ WB, but this is for your own info, and in case they ask you questions. The aperture the size of the camera eye's opening. The smaller the number of the aperture, the more light is allowed in (the bigger the opening). Aperture numbers typically range from f/2.5 to f/11. The larger the number of the aperture, the sharper the entire image, the greater the "depth of field." With a small-numbered aperture, on the other hand, one part of the image may be in great focus, whereas the rest of the image may be out of focus. Playing with shutter speed and aperture gives you great power over the image on the whole. A photograph is not just a "copy" of real life. The photographer is an artist, and every photograph carries an imprint from whoever made the photo. A good photographer has a solid technical knowledge of the camera and just how to use it for each situation, is flexible to changing circumstances, understands weather and lighting (mornings and evenings make the best photos), and has an "eye" for catching moments and framing them in just the right way. Basically, a good photographer is a light-moment-and-camera ninja.