Originally posted by beholder3 Dynimc range pretty much is maximum contrast between values
Ya, you mean like in a 8 bit system the exponential difference between the lowest possible value and the highest possible values?
Contrast is the ratio between the lowest and highest value, on an 8 bit system the lowest recorded value is 1 (all zero does is tell you you didn't actually record anything), and 256.
I think that's what I said.
Quote: The upper end is when you hear something so loud it physicslly damages your ears.
With photos it is the same.
The upper end has nothing to do with ear damage, only with output volume. (or input volume.) DB is exactly the same kind of measurement EV is, an exponentially increasing value. With photos, in my imaginary 8 bit camera system, any value that would record above 255 is recorded as 255. It could be 5 EV higher using the scale, but the sensor EV DR doesn't cover the full range of the scene, so on my K-3 1EV - 13.9 EV can be recorded, anything over (say a light intensity that should be represented by say 1024), can only be recorded as 255.
Quote: On the data side please keep in mind gamma curves which allow a few bits to contain big contrasts. So on 8 bit the broghtest white can be much more bright than just 256x the darkest value.
That explanation creates its own illusion. In nature you can have contrasts up to 22,000:1. The best you can do for contrast on any output device that I know of would be 500:1, using Dynamic Contrast, which is really just another ordinary 150-300:1 TV with a shifting curve. You are actually going to have to compress you images to get them to look right on your very limited output device. If you start mapping two bits onto one to increase contrast, you'll vastly under-expose your shadows and blow out your highlights. What happens with all systems is you compress your DR into blacks and white suited to an 8 bit jpeg. 1-255. From there you could conceivably expand you values to create more contrast to create more DR, but you'd have to have an output device that could handle it. Some of us deliberately under-expose because it creates more realistic looking contrast in the low end., but we have to clip the high end in some scenes to do that. Some of us buy large output amplifiers and then never turn them up over 1or 2 because we get cleaner sound that way, the sound analogy only goes so far. With sound we usually have to limit the capacity of our output device. In digital photography we are always pushing our output device to the max to get the most realistic looking image.
The most contrast you will be getting out of a print will be about 120:1, newspaper or magazine 60:1. Some monitor's and TV s can slide the curve up and down to achieve contrast approaching 500:1 I believe, but not at the same time. They do it by shifting the curves so when they are at their brightest, they can't display their darkest dark at the same time as their brightest bright.
There is no output device that can come anywhere close to the 20 EV you can have outdoors. No input device either. You squeeze your 20 EV external scene's DR into 14 EV on your camera, which you then reduce to 9 EV max (and probably considerably less) on you computer monitor or TV or max. or 7 (and probably considerable less) EV on a print.
And mapping multiple pixels onto one to create contrast will create banding really quick. As will extending the contrast values by remapping pixels values.
It seems to me you're for the most part repeating what I said in your own words. Maybe you find your way of explaining it clearer, but there's couple flaws there that needed to be cleaned up.