Technically well stated, Steve. My point is about the difficulty in defining the general visual impact tolerated. That's a job for each viewer.
Jack --- On Mon, 4/5/10, steve harley <p...@paper-ape.com> wrote: > From: steve harley <p...@paper-ape.com> > Subject: Re: Define "blown out" :-) > To: "Pentax-Discuss Mail List" <pdml@pdml.net> > Date: Monday, April 5, 2010, 10:52 AM > On 2010-04-05 11:27 , Jack Davis > wrote: > > I'll offer mine the nebulous term by saying that if at > least some surface areas are rendered featureless by virtue > of being too bright, I'd consider those areas "blown out." > Many images can tolerate a certain amount of this condition, > but it's amount is the criteria and varies with each viewer. > Said areas must, of course, contain some available mask > detail which defines the surface. > > IOW, I'm not talking about an absolute ball of glare > wherein no detail is discernible. > > in digital signal processing "blown out" is commonly called > clipping -- parts of the signal are too strong to fit within > the dynamic range of the analog-to-digital conversion > process; whether it is a matter of the sensor's capacity or > of what is done with the signal from the sensor, it still > comes down to the fact that with digital signals, there is > no way to "turn the volume to 11" > > there are some subtleties for digital images, since there > are red green and blue "channels" (to use Photoshop lingo), > one channel may be blown out, or clipped, while the others > still have detail; in such cases the resulting image may > still be quite usable > > the same problem occurs at the other end of the dynamic > range, loss of shadow detail when the image content is "100% > black" > > > -- PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link > directly above and follow the directions. > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
