All digital cameras have a fully automatic shooting mode where the camera will take care of all the settings for you, but you can take much more control over the kind of pictures you can get if you use semi-automatic or manual shooting modes. These are sometimes known as Creative modes.
The two most important creative modes are Aperture Priority (usually indicated by the letter 'A' on the dial, but Canon call it 'Av') and Shutter Priority ('S' on the dial or 'Tv' on a Canon).
It is by using and mastering these modes that your photos begin to change from being bog standard snapshots to something altogether more engaging.
It is not as difficult as you may think to master using these modes. Just like learning anything else, all it takes is a basic understanding of the affects you can create followed by plenty of practice with the camera in your hand.
Examples of what you can achieve through setting shutter speed and aperture size include freezing motion and including motion blur in your photos. You can also throw the background of a photo out of focus to accentuate your subject.
Aperture Priority allows the user to choose the size of aperture the camera will use to take the picture. This allows creative control over depth of field, which is the range of sharpness that will be produced. Using a big aperture gives a very shallow depth of field which means your subject will be in sharp focus but the background will be blurred, making the subject stand out more. This is ideal when shooting portraits.
A small aperture, on the other hand, gives greater depth of field, meaning the background as well as the subject will be sharp. This is more useful for subjects such as landscapes. Something else to look out for is a depth of field preview button. Not all cameras have one these days, but it can be very useful, as it allows the photographer to see what range of sharpness they will get with any given aperture before actually taking the picture.
Shutter Priority allows the user to control how long the camera's shutter will stay open. This is important when shooting pictures of moving subjects. If you take a picture of something that is moving and you use too slow a shutter speed the picture will be blurred. To freeze a moving subject you need to choose a faster shutter speed.
Sometimes, though, you may actually want to see some motion blur in your picture. A picture of a waterfall, for example, can be transformed by using a slower speed to create a milky, flowing look to the water, rather than a fast speed which will freeze every droplet of water.
Whilst aperture-priority and shutter-priority modes may offer all the creativity that many photographers will ever want, and while it may be that controlling either aperture or shutter speed is enough to think about, the ultimate control can be gained by putting the camera into full manual mode.
Manual shooting requires the user to set both aperture and shutter speed, which requires a good understanding of how the two work together, although the camera will give some help in metering and suggesting the correct settings. For many professionals, though, it is the ability to ignore the camera's advice and deliberately set it to expose darker or lighter that makes them choose manual mode for the ultimate control over exposure.
Digital SLR Basics
Digital SLRs and Digital Cameras Key Differences
Digital SLR or Compact System Cameras
Digital SLR Handling
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Learn More About Features
Resolution and Sensor Size
Manual Exposure Modes
Help With Tricky Lighting
Live View and Articulated Screens
Depth of Field Preview Button
Current and Recommended Models
Summary of Current Models
Recommended Digital SLRs
Digital SLR Guide Author
This guide was written by Ian Younger
For some types of picture you need to use very long exposures. If you want to take pictures of the stars for example, you may need to leave the shutter open even longer than the typical 30-second longest shutter speed. To do this you need a camera that has a 'B' or 'Bulb' setting, which allows the shutter to be locked open for as long as you want.
Don't forget, also, that taking a picture involves some movement by the photographer. Any slight shakiness of your hands or jogging the camera when you press the button can lead to blurred pictures, so that's another reason for taking control over the shutter speed and making sure you use a fast enough speed to avoid any camera shake.
When using slower shutter speeds you can, of course, put the camera on a tripod to hold it steady, but even then the action of pressing the shutter release button can slightly jog the camera and cause blur. That's where it is useful to have a camera with a self-timer feature, which allows the camera to fire itself after a short delay (usually 10 seconds after you have pressed the button).
Another factor that can cause a very slight lack of sharpness is the movement of the mirror inside a DSLR. As the mirror moves out of the way it can cause tiny vibrations and this can mean your picture is not pin-sharp. To prevent this problem you need a camera that features mirror lock-up. This allows the mirror to be locked out of the way of the sensor before the shutter opens to capture the image.
Fast Shutter Speed
Slow Shutter Speed