I don't think your use of "tonal range" is correct here. The tonal
range of the input is what it is. Somewhat greater in a raw file than a
JPEG with perhaps up to 1 stop or so of additional highlight and shadow
detail. But the tonal range of the 12 or 14 bits is not improved by
converting to 16 bits... it's only scaled upward. For example, with 12
bit input the maximum value for pure white is 4095. In 16 bits it's
16535 or 16 times larger. During the conversion of 12 bits to 16 bits
all the 12 bit values are simply multiplied by 16 and 4095 becomes 16520
(as close as you can get to 16535 on an integer conversion).
The advantage of the 16 bits is that the additional range over the JPEG
is retained and, as you frequently point out, editing produces fewer
integer truncations and star-stepping when dividing numbers downward
when reducing pixel brightness during editing.
Chuck Norcutt
Moose wrote:
> Moose wrote:
>
>> ... In reality, RAW files are 12 or 14 bit. RAW converters are
>> capable of reading all thos bits at once and outputting 16 bit
>> files. They have a greater tonal range than the input, so
>> everything in the RAW file is available in one conversion.
>
> I should have been more precise: "They work in 16-bit and are capable
> of handling a greater tonal range than is in the input, so everything
> in the RAW file is available in one conversion."
>
> Moose
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