Big Ben's Panorama Tutorials

Colour Correction and Digital Cameras

The previous example used film for the source images. Due to the limited dynamic range of digital cameras colour correction is of limited use. Below is a repeat of the exposure correction test using a digital camera.
 
Relative 
exposure
(f stops)
Original
Image
Reference
Image
Corrected
Image
-3
-2
-1
0
+1
+2
+3
+4

Some things to note:

  • The shadow detail is better in +1
  • The highlight detail is better in -1
  • The highlight detail in the corrected +1 image has already been reduced to noise, and spreads rapidly across the image as exposure is increased.
  • Shadow detail can be extracted from underexposed images but the colour begins to degrade at -2 and noise is unacceptable at -3.

Film vs Digital.

Below is a comparison of the corrected images from both tests. While the film image appears to have a lower contrast, this is because it contains far more detail in the highlights and shadow. The equivalent detail in the digital images is spread across exposures from +- to -1 (see above).

The biggest difference between film and digital is that film does not have a distinct cut off of detail at under and over exposure. The information in under and over exposed regions is somewhat compressed, but it is still there. Once a digital image is overexposed, there is no information left to retrieve.

Relative 
exposure
(f stops)
Corrected
Image
Corrected Film
Image
-3
-2
-1
0
+1
+2
+3
+4

 


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This page, its contents and style, are the responsibility of the author and do not represent the views, policies or opinions of The University of Melbourne. All photographs Ben Kreunen 2000

Ben Kreunen <bernardk@unimelb.edu.au>
Department of Pathology
Last modified: February 24, 2003