Big Ben's Panorama Tutorials

Dynamic Range

Calculating Dynamic Range

I have devised a simple test to calculate the dynamic range of any imaging system.  A test subject is photographed at a wide range of exposures, digitised and then inspected to see whether a change in image brightness can be detected. 

Test Subject

The test subject consists of a grey rectangle in the middle of a page with background split into black and white.

   

 

   
 

 

 

 

 

 

 

 

   
   

 

   
  • The grey rectangle represents a single exposure value of the current exposure.

  • The difference between the grey rectangle and the white portion of background represents a subsequent increase in exposure.

  • The difference between the grey rectangle and the black portion of background represents a subsequent decrease in exposure.

Acquiring Images

Digital Film
  • Set your ISO to its lowest possible value (unless you want to test a higher ISO of course)
  • Turn off all pre-processing (sharpening etc...)
  • Save your images in the highest quality format, preferably RAW
  • Acquire your images at the greatest bit depth
  • Shoot exposures ranging from -7 stops to +13 stops
    This may require bright conditions to keep exposure times reasonable
  • Reset the scanner to factory defaults
  • Turn off autoexposure and all pre-processing (sharpening, dust removal etc...)
  • Set desired colour model and scan at the highest possible bit depth.

Once you've collected your images you're ready to evaluate them.

 


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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