Digital Photography

Digital Photography Tips 6

Shutter Speed

Shutter speed is the amount of time that the digital camera is open for to let in the light to capture that image on the digital camera sensor. Shutter speed is used to control how you want your image to look, particularly if the subject is in motion. Also shutter speed can be used to reduce the blurring in the digital photograph due to camera shake. A general rule of thumb is that for fast moving sports, use a fast shutter speed. For surfing photography, for example, a shutter speed of greater than 1/500 is used and 1/1000 is the most commonly used shutter speed that will capture the swiftly moving surfer on a wave. Motor sports may require a faster shutter speed. Use slower shutter speeds for moody atmospheric, landscape shots, or low light conditions, to allow as much light in as possible.

Aperture

Aperture is a measure of the hole that lets the light in onto your digital camera's sensor. Aperture is measured in f-stops and is used to control the depth of field(DOF) which is the amount of the image that is in focus. Most lenses can use apertures from f/4 up to a maximum aperture of f/22 or f/32. To isolate a subject from the background use a large aperture such as f/4 or f/5.6 which will give you a small depth of field. Some digital cameras have a depth-of-field preview button which you can check. If there is not enough depth of field, use a slightly higher aperture. Landscape photographs need higher apertures to keep the maximum foreground to background detail and a typical value for landscape photography could be f/22. Because of the higher aperture, your shutter speed will be relatively slow. The different shutter speed and apertures needed to let the same amount of light in is called the exposure ratio.

Program Modes

Digital Cameras have a number of program modes that allow automatic and semi-automatic exposure settings. Tv is Shutter Priority which allows you to set the shutter speed and the camera will automatically select the correct aperture according to the current lighting conditions. Av is Aperture Priority and will allow the camera operator to select a specific aperture setting such as f/5.6 and the digital camera will select the correct shutter speed for you that relate to the light conditions when you are taking the photograph. If you want the fastest possible shutter speed for a photo, select the minimum aperture that your lens will allow when you are in Aperture Priority mode. Manual mode will allow you to select the Aperture and Shutter Speed manually for yourself.

Histograms

Using the LCD histogram can help you fine tune your exposure and provides a graphic picture of a photo's colour range. The horizontal axis of a histogram shoes you the brightness level and the vertical axis gives you the number of pixels recorded for that level. The dark or black end of the spectrum is at the left end and the light or white end of the spectrum is at the right of the histogram horizontal axis. Have most of your image in a nice bell curve in the center of the graph or slightly to the right. There is a theory which claims that the bell curve should be hard up to the right of the histogram, thus giving you most signal-to-noise ratio, thereby eliminating more noise from the digital photograph. Other experts claim that the histogram should be slightly to the left of center, thereby rendering the digital photograph slightly underexposed. Take your pick and do your research and testing.