this is from a thread i posted on another forum but it may explain some basic terms for you
Aperture - this is the hole in the lens which lets light through, it can be made bigger and small, much like the pupil of your eye, this size of the hole is measured in f stops/numbers.
this bit is a little confusing at first but the smaller the hole the larger the f number
large f number (f22) small aperture .......... small f number (f2.8) large aperture
Shutter Speed - this is the amount of time the shutter stays open, allowing light to fall on the film/ sensor
ISO - on a digital camera this is the digital equivalent of film speed. high iso settings will enable you to shoot in low light conditions, however high iso setting cause heavy grain / noise just like a high speed film (note that digital noise is far more destructive to an image than proper film grain)
Exposure - this is the overall effect caused by relationship between aperture and shutter speed. for example if an image is underexposed not enough light is reaching the sensor/film, this is either because the shutter speed it too fast or the aperture(hole) is too small
Bracketing - is a technique used in difficult lighting condition where there are areas of strong highlights and shadow. in order to capture the perfect exposure 3 seperate image must be taken, metering for the highlights, midtones and shadow.
-1 ........................... 0 (correct exposure) ......................+1
Depth of Field - The amount of area that is infocus infront of the subject in the ratio 1/3 infront and 2/3 behind. this area is determined by the selection of
aperture
for a large depth of field use a large f number (f22) (small aperture), for a small depth of field use a small f number (f2.8) (large aperture)
example of f2.8
example of f8
.
