Back to photo classes menu Home

Below are links to some tutorials on point of focus and exposure

When the shutter button is depressed half-way two things are established:

(a) The exposure ie the amount of light to be let in via the aperture.

(b) The point or points of focus ie the part of the picture that will be in true correct focus.

Both these setting can be adjusted on most cameras to concentrate either on an average of all of the shot or a specific area or point and can be set independantly of each other, so you can use matrix exposure metering with spot point of focus or vice versa etc.

Have a look at some of these and it may all become clear! Remember look on youtube for information on your camera as well as on Google.


What have we learned so far?
1. A digital image is a wall built with coloured bricks each bearing a unique number which links to a colour shade.
2. Photography is all about LIGHT - Always be aware of your light source and how your camera reacts to it.
3. Light comes through an adjustable hole called an aperture. The size of the aperture is measured in f-numbers. The larger the f-number the smaller the hole and vice versa.
4. Images are made by the shutter allowing light through the aperture for a specific amount of time measured in fractions of a second.
5. Your camera will automatically calculate the amount of light needed for an exposure but we can adjust for under and over exposure.
6. Your camera sees in planes and your image will be absolutely sharp only at one plane - remember the three chairs. The picture in front of and behind this "plane of perfect focus" will become progressively out of focus "fuzzy"
7. Your exposure and point of focus is determined when the shutter button is depressed half-way. Your picture can be re-framed whilst the button is held in that position and the "plane of focus" will remain set.

Camera adjustments
(1) Charge your battery
(2) Use an empty memory card
(3) Set your camera to produce the largest and best quality image possible i.e. least shots per card.
(4) Set your automatic focus "af" point to "fixed" preferably in the centre.
(5) Set your exposure. Choose evaluative, spot, partial depending on your preference.