Shutter speed, ISO and the f stop
Task. Take a photo using your camera on automatic. View the photograph on your camera. On automatic your camera will have chosen the 'best settings' to take the photograph. It may have fired the flash if it doesn't think there is enough light
Look at the screen and the image on the back of the camera.
The camera will have chosen
an ISO for you
ISO is a measure of how light sensitive the sensor in the camera is). On a film camera this was between 100 - 1600, on modern SLR digital cameras the highest ISO might be 3200 or 6400. The higher the number the more light sensitive the camera
a shutter speed
A speed that will allow the correct amount of light into the camera to take a tonally balanced photo
an F stop
f stop is a measure of the size of the hole in an iris between the lens and the shutter, this controls what the camera is focused on and how much light gets into the camera) f4.5, f5.6 f6.4 f8 f12. The higher the number the further this distance that is in focus. We call this depth of field. But the higher the number the smaller the hole and again the less light that is entering the camera
Shutter speed.
This is displayed as a fraction. A fraction of a second
1/2000, 1/400, 1/200, 1/125, 1/80, 1/50, 1/25,
The is an indication of how long the shutter will be open. The higher the number (well strictly speaking the smaller the fraction) the less time the shutter is open.
The less time the shutter is open the less light enters the camera
ISO
This is an indication of how light sensitive the camera is. The higher the number the more light sensitive the camera is and the less time you will need to have the shutter open. Different cameras have different ranges of ISO 100-1600 used to be standard, newer more sophisticated cameras will be capable of higher ISO settings
FStop
Fstop is a way of manually changing the size of the hole in the camera behind the shutter. This iris controls what the camera is focused on and again how much light enters the camera
Your eye functions in the same way. The iris around the pupil expands or contracts to change what the eye is focused on. Try leaning in close to a mirror and you might see the iris change size
All of this helps you create the perfect photo. You can change all three settings to create the photo you want
The Light metre on the camera visible through the eye piece or on the screen on the back of the camera will help you balance the light coming into the camera
Think of it as hitting a bullseye. As you change the settings a line with move. You are trying to get the line on the zero in the centre (personally I put it slightly to the left as digital cameras seem to tend towards over exposure and making the shot too light)
If the line is too far to the left your photo will be too dark, too far to the right and the photo will be too bright. You can see the camera in this shot is set 1/13 (a very slow shutter speed) F5.6 almost the largest hole in the iris and ISO of 100 which is slow suggesting very bright sunlight.
Photographers talk about the Exposure Triangle. Indicating how the three elements Aperture (the size of the hole in the iris), ISO and Shutter Speed are equally important when it comes to taking the 'perfect' photograph. Its a game
But and this is crucial
There are some rules if you like, that will control the settings you choose
Shutter Speed. Faster - less light, Slower more light but there is more chance of camera shake or motion blur. Unless you have got hands that are steady as a rock you will find slower than 1/100 and you will get blur. I was always taught to go no lower than 1/125. At the other end higher than 1/240 or 1/300 will freeze movement, a jumping figure will be forever frozen in mid-air.
Careful sometimes a photo that looks perfect on the viewscreen on your camera will be very blury when viewed full size.
Trick/Tip In low light situations when photographing a landscape or something that isn't going to move much you can use a tripod or rest the camera on a flat surface and use the timer. This will remove camera shake. Sometimes the contrast between blur and crisp can be part of the appeal of a photo. Try a camera on a timer with a slow shutter speed on a tripod or on a flat surface taking a shot of a running tap or running water
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| This is a tripod photo of a waterfall with a 5 second exposure, the light coming into the camera has been balanced with a very high fstop and the lowest possible ISO |
Task Try a fast shutter speed 1/300 you will need a higher IS0 and a low fstop to get the maximum amount of light into the camera. You will also need to be outside to make sure there is the maximum amount of available light
ISO It sounds odd but you want to keep the ISO as low as you can. An ISO of 100 will give the most crisp image. The higher you go with ISO the more light sensitive the camera becomes. The camera will become too light sensitive and the camera will become over sensitive to light and the photo will become grainy as the cell in your camera picks up more and more frequencies of light
FSTOP. The higher the fstop the greater the distance in your photo that will be in focus but the higher the fstop the smaller the aperture or hole in the iris and less light will be allowed into the camera.
Classwork Task Working both inside and outside under a range of lighting conditions your task is to produce a series of portraits and landscape shots noting the ISO, fstop and shutter speeds for each shot. Your camera will do this tagging each shot for you, but writing them down is a good habit to get into.
Independent Task
1. Own version of these notes and Exposure Triangle in your sketchbook. This is essential
2. Print off photos you have taken (variety of sizes...majority small, a few you are pleased with A5 or A4) annotating with ISO, Shutterspeed and fstop. Annotate with your own notes (what went well, what you would change etc etc)
Best of luck....I look forward to seeing what you come up.
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