On Sat, 12 Jan 2019 09:31:44 -0500, Alan Browne
wrote:

On 2019-01-11 20:06, Eric Stevens wrote:
On Fri, 11 Jan 2019 12:42:13 -0500, Alan Browne
wrote:

On 2019-01-10 22:52, Eric Stevens wrote:
On Thu, 10 Jan 2019 07:39:32 -0500, Alan Browne
wrote:

On 2019-01-10 04:05, Eric Stevens wrote:

According to nospam they are claiming a DR of 14.3 for the sensor of
the D800. As they said in the link that I posted which has somehow got
snipped "Maximum dynamic range is the greatest possible amplitude
between light and dark details a given sensor can record ...".

1. A 14 bit sensor cannot, possibly, record 14.3 DR.

Please read what I am about to write and give it deep consideration
before you reply.

_There_is_no_such_thing_as_a_14_bit_sensor_! Or a 12 bit for that
matter. The sensors which we are considering are *analog* devices
which are not digital in their operation.

12 or 14 bits only come into it after the analog signal is stripped
from the sensor and (only then) passed through an analogue to a
digital convertor (ADC).

Now you're being silly.

The whole point of the ADC is to sample the analog sensor.

Constrain that to 14 bits and that's all you get. The whole point of
"more bits" in the ADC is not to find "bright" signal, but to sample
down deep in the very smallest shreds of the darkest part of the signal.

All of which is completely true. But how deep down are the shreds of
the darkest part of the signal. And how bright is the brightest part
of the signal before it overflows into blooming? It is the difference

If the photographer exposed correctly, other than some (acceptable for
esthetics) hotspot here and there, then it's pretty moot.

Blooming is more than a hot spot. Its a general overflow.

The physical truth of the matter is that deep down at the shreds lies
noise. Usually a lot more noise than signal.

Yep. An interesting point: according to DxO, when the test uses a
paper target, some of the noise may actually be the texture of the
paper of the target.

between these that determines the dynamic range of the sensor. The
fact that the DR is scaled to 14 bits is of secondary consideration.
If 14 bits is all that ammters why go to all the trouble and expense
of developing high DR sensors? Let's have a cheap sensor and hang it
on a 14 bit ADC.

As I pointed out several times engineers will usually "right size" the
ADC to the sensor if maximum signal performance is desired. So if they
put in a 14 bit ADC, there is likely less than 14 bits of
honest-to-goodness signal.

IOW: You're peddling hard to fit 7 pounds of **** into a 5 pound bag.

True, but fortunately DR is compressible.
--

Regards,

Eric Stevens