Backwards thinking on your part. Linear may be technically correct, but non-linear is better, it's what film has done for years and years. The irony is that linear capture produces a non-linear greyscale, the brightness of each step is double or half of the neighbouring steps.
The steps starting at 0,0,0 on the left take half the bit depth to just get out of the blacks, the suddenly leap up to saturation in just the top 4 stops. The reason we are fooled is that the greyscale horizontal axis is progressively compressed, not only should each step be double the brightness of its predecessor, it should also be double the length of its predecessor. But it's not; it's NON-linear, because it was captured lineally. Film produces a constant increase in brightness from each stop to the next whether they are shadow or highlight stops. A difference of a few lumens in the shadows will give the same increase in brightness (negative density in this case) as will an increase of hundreds or more lumens in the highlights. With linear (digital) capture, a shadow stop may represent, let's say, 4 lumens increase over the previous stop, while a 5 stops brighter highlight will represent 128 lumens increase over the previous stop. That's 32 times more illumination, but it's still just one stop! And guess what? The digital sensor will record that as a 32 times higher increase in brightness in the output file. IOW a shadow stop is a severely discounted commodity. It's all about how our eyes see versus how sensors see. The sensor may technically be correct, but I want to photograph things the way that I see. Regards, Anthony Farr > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ryan > Brooks > Sent: Friday, 18 August 2006 1:22 PM > To: Pentax-Discuss Mail List > Subject: Re: Tonal gradation in shadows - The $67 Question? > > > Except that the sensor is linear- if it's a CCD anyway. It's a photo > (okay, electron) counter. If you digitize the output in a non-linear > space, you're not getting as much (good) information as if it was a > linear digitization. > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
