Full PDF of this week's lesson: http://sites.google.com/site/biowbiow002/02-ISOShutterSpeed.pdf
ISO, or film speed, is really just a setting to determine how quickly an image will be captured by either the film or digital sensor. The higher the ISO, the quicker the image will be captured and the less light that is required.
The lower the ISO, the longer it takes for the image to be captured and the more light you will need.
general rule of thumb:
100 - 200 sunny and outdoors
400 in the shade, overcast, indoors with good light
800 - 1600 indoors, low light conditions, sports or action
After you’ve considered your ISO it’s time to think about shutter speed.
Your shutter speed is how quickly the shutter, or the little door that opens in front of your film or image sensor, operates. It can range from several seconds (or minutes on the Bulb setting) to 1/1600 of a second or faster. It might help to visualize your shutter literally as a door, with your shutter speed controlling how fast or how slow the door opens and closes. A faster shutter speed will freeze action whereas a slower shutter speed can create a blurred effect (or can just be downright blurry.) When you set your shutter speed on your camera, you’ll see numbers like 60, 120, 250, 1000 and so on. These actually represent 1/60th of a second, 1/120th of a second and so on. So the higher the bottom number on the fraction, the faster the shutter speed. The smaller the number, the slower the shutter speed. You will also see shutter speeds for seconds, indicated by inch marks ("). For example, if the display says 1"5, that indicates a shutter speed of 1½ seconds. If the display says 30", the shutter will be open for 30 seconds.
general rule of thumb:
use a tripod or flat surface to steady your hand for anything 1/50th or under
if you are handholding, use a minimum of 1/60th. Hold your breath while taking the photo to reduce camera shake.
fast moving objects require at least 1/1000 to freeze the action.
Weekly Challenge: Kitchen Sink Test
Set your camera to Shutter Speed Priority (S or TV mode). If you are inside, set the ISO between 1000 - 1600.
1. Find your kitchen sink (that shouldn’t be too hard.)
2. Now locate an object that is going to obstruct the water flowing from the faucet, like a cup. Place it below the running water.
3. Set your shutter speed to 1/80th of a second (indicated by the number 80.) Turn on the water and take the picture.
4. Now set your shutter really high (around 1/1000 of a second or higher) and take the photo again.
***Bonus points: Grab your tripod and set up your shot again using a really slow shutter speed, such as half a second, indicated as 0"5, or 1 second, indicated as 1". What effect does that give you? In what situations can you use this effect?****