Digital Photography Tips

Excessive JPEG compression

 
 
 
 
 
 
 
 
 
 

Digital shooting mistakes—and how to prevent them

 

Excessive contrast

If you've shot on days with harsh sunlight, you've probably noticed that many of your digital images exhibit extremely high contrast. Such pictures include dark shadow areas and ultra bright highlight areas. Excessive brightness is the most serious problem, with "burned-out" or "blown-out" highlights that obscure detail in, for example, a bride's white gown or a snow covered hillside. With sophisticated image-editing software such as Microsoft Digital Image it's easy to solve certain technical problems. However, it's almost impossible to fully correct blown-out highlights. While these can be darkened, you cannot add detail or texture that was not recorded by the image sensor.

The Fix

In order to minimize this problem, remember the following tips:
If your camera offers a contrast level adjustment control, do not select the high option.
Even in the soft light of a cloudy day, the standard setting should produce snappy
contrast. If your camera does not have a contrast control feature, try to take pictures
when a cloud drifts over the sun. The contrast will be lower under those conditions.

  • In extremely harsh, contrast light—as on a sunny day—select a slightly lower contrast setting. This will minimize excessively bright highlights and extremely dark shadow areas. After downloading images to a computer, use image-editing software to increase contrast if the pictures seem a bit "flat." (The software is more effective in increasing rather than reducing contrast.) When taking pictures of people, ask them to move to a shady area and use flash to maintain a bright effect.
  • In direct sunshine, use the camera's "Flash Always On" option for nearby subjects to even out the lighting. The burst of extra light can moderate contrast by brightening shadows. If your camera's flash unit produces ultra-bright highlight areas, don't use it with white subjects.
  • Overexposure compounds the problem of contrast by making highlighted areas excessively bright. After taking the first picture of any subject, check the exposure in the camera's monitor. If the image seems too bright, set a negative exposure compensation factor such as -0.5. Re-shoot the picture and check it again. A slightly dark image can be corrected later with image-editing software, using the fill-flash or lighten tools.
   
   

For more information contact: Bob Hahn bob@ScubaPhotos.org Phone: 610.868.0339