Think of it like a ruler. It's 1m long so we can say that it has a dynamic range of 1 meter.
Now a 1-bit ruler has a mark at the 50 cm point.
and a 2-bit ruler has marks every 25 cm
an 8-bit ruler has 255 marks between 0 and 1 meter.
and a 16-bit ruler has just a little more than 65 500 steps. The dynamic range is still 1 meter.
and a 16-bit ruler has just a little more than 65 500 steps. The dynamic range is still 1 meter.
There has been much discussion about working in 16-bit or 8-bit and the concensus is that until there is a 16-bit output device (Printer mostly) there isn't really much point in working in 16-bit and then converting it back to 8-bit.
Photographs are made for human eyes. All the mathematics in the world won't make a bad image look good. Do a simple experiment.
1. Open a RAW file as a 16 bit image. and as an 8-bit image.
2. Make an action that does a number of pixel-changing things to the image
like levels, curves, saturation and hue etc., Be tough on the image!
3. Run the action on the 16-bit image and then on the 8-bit image.
Convert the 16-bit image to 8-bit and print them both out.
See if you can see any difference.
Let me know which one is better, if any.
Herschel
karl shah-jenner <shahjen@xxxxxxxxxxxx> wrote:
: Karl, I'm afraid you've got the whole thing a nit garbled. It's the
gradation steps that become smaller. Not the total luminance levels.
I know that, it's just that I find *many* web pages saying that the
'dynamic range' of a jpeg is 256 steps (true) that this equates to 2.4, and
*thus* 8 stops (!) of luminance values, then they conclude that raw or
tiff has a greater range of luminance values because it has a greater bit
depth (eek!)
: One bit records from pitch black to gleaming white. The same with 2
bit. But the difference is the number of grey tones in between.
I know that too..
the problem seems to be that film 'dynamic range' and sensor dynamic range
is totally different to the concept of dynamic range equating to bit
depth - which is false :)
..as I showed with that little test shoot
k
Herschel Mair
Head of the Department of Photography,
Head of the Department of Photography,
Higher College of Technology
Muscat
Sultanate of Oman
Muscat
Sultanate of Oman
Adobe Certified instructor
+ (986) 99899 673
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