At 09:16 PM 10/10/2006, Joseph Chamberlain, D.D.S. wrote:
Jeff and Lea: Another important aspect of working with histograms is the fact that the information displayed is not based on the RAW capture but rather on the JPEG preview instead. Since JPEGs are limited to 8-bit (format limitation) while RAW images are captured in 16-bit, it is very clear that a lot of the information captured is not being displayed by the histogram.
Yes, and the histogram of a RAW file would be meaningless to anything but a RAW converter.
So while the histogram may be showing blown highlights, a lot of the information that was clipped when the image was converted to JPEG to create the preview is still there in the RAW file to be explored and manipulated.
There may or may not be information that was clipped. Depending on the scene, the jpeg can represent all the data that was there, albeit in a compressed way. However, the difference between a luminosity histogram and RGB channels histogram will always be significant. There is an interesting comparison on this page:
http://www.slrcamerainfo.com/article.php?filename=Dynamic-Range-and-Clipping Jeff Spirer Photos: http://www.spirer.com One People: http://www.onepeople.com/
