Finally got to the point where no new camera holds my interest(waiting for specific offering)

On Fri, 11 Jan 2019 23:21:43 -0500, nospam
wrote:

In article , Eric Stevens
wrote:


EV's are equivalent to stops for any purpose related to exposure.

I can change exposure value without changing the stop setting.

No ****. That's sort of the point.

It's my point. Stops aren't exposure values. Exposure values are not
stops.

they are.

Lets leave it at that.

ok, but you saying so doesn't make it correct.

Allright then. Please explain to your readers how you set a lens to an
EV of 20.

For what ISO and speed?

No, no. No ISO or speed. The lens calibration is equivalent to stop
settings according to nospam so it must be possible to set a lens to a
particular EV. I picked 20 as an example.

by picking 20 (or any number), you demonstrate you don't understand it.

Now if I said, for example f/11 you would understand it. But that is
not an EV.
--

Regards,

Eric Stevens

On 2019-01-11 18:18, Eric Stevens wrote:

The recorded output of the ADC is limited by the capabilities of the
ADC. But these have no effect on the capabilities of the sensor. If

If there is no way to encode the information, then that is the mootest
of moot points.

--
"2/3 of Donald Trump's wives were immigrants. Proof that we
need immigrants to do jobs that most Americans wouldn't do."
- unknown protester

On 2019-01-11 18:20, Eric Stevens wrote:
On Fri, 11 Jan 2019 12:51:28 -0500, Alan Browne
wrote:

On 2019-01-11 10:28, nospam wrote:
In article , Eric Stevens
wrote:


The problem is clearly DXO's testing methods. No matter how you look
at this, you have to be able to imagine all kinds of sources of
inaccurate measurements, especially if they are slight. I have to
agree with nospam and Alan. You can't get DR outside of the limits of
the ADC because that is the output you see, but you can certainly get
test results outside of that limit.

But the digital DR of the output of the ADC is not the same as the
analog DR of the sensor. Nor is there any reason why it should be.

nobody said it was, however, it's always going to be limited by the adc.


Got that Eric?

What is 'it'? The DR of the sensor or the DR of the output of the ADC?

Obvious. The ADC is the limiting factor. Always. There is NO WAY for
DxO to probe the sensor directly (and it would be meaningless to
everyone even if they could...)


--
"2/3 of Donald Trump's wives were immigrants. Proof that we
need immigrants to do jobs that most Americans wouldn't do."
- unknown protester

On 2019-01-11 18:34, Eric Stevens wrote:
On Fri, 11 Jan 2019 11:15:19 -0600, Bill W
wrote:

On Fri, 11 Jan 2019 21:30:23 +1300, Eric Stevens
wrote:

But the digital DR of the output of the ADC is not the same as the
analog DR of the sensor. Nor is there any reason why it should be.

Well that's exactly what I said. If they are publishing the DR of the
sensor, why would any photographer care about that, if the DR is then
limited by the ADC? The usable output of any camera we buy is all we
care about.

There is no reason why the DR of the sensor should not be compressed
to make it fit within the limits of the ADC.

Already explained to you: compression does not improve DR without
consequences in quality elsewhere.


--
"2/3 of Donald Trump's wives were immigrants. Proof that we
need immigrants to do jobs that most Americans wouldn't do."
- unknown protester

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.

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

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.

--
"2/3 of Donald Trump's wives were immigrants. Proof that we
need immigrants to do jobs that most Americans wouldn't do."
- unknown protester

On 2019-01-11 20:20, Eric Stevens wrote:
On Fri, 11 Jan 2019 12:44:39 -0500, Alan Browne
wrote:

On 2019-01-10 23:04, Eric Stevens wrote:
On Thu, 10 Jan 2019 07:44:43 -0500, Alan Browne
wrote:

Wow! You could pass Photography 101, chapter 3 (Basics of exposure).

CONGRATS!

Now you have followed me that far, you may be interested to see
https://upload.wikimedia.org/wikiped...Ib_with_EV.jpg

Notice how the bottom of the shutter speed ring has a pointer with
which you can set the EV. That enables the aperture ring (dimly seen
behind the pointer) to be moved in synchronism with the shutter speed
ring so as to maintain constant the preset EV. This is an early
pre-prescient camera. According to nospam modern cameras don't need
the EV to be set. The aperture ring knows the EV all on it's own.


You're being willingly and deliberately obtuse.


--
"2/3 of Donald Trump's wives were immigrants. Proof that we
need immigrants to do jobs that most Americans wouldn't do."
- unknown protester

On 2019-01-11 20:29, Eric Stevens wrote:
On Fri, 11 Jan 2019 12:50:41 -0500, Alan Browne
wrote:

On 2019-01-11 03:46, Eric Stevens wrote:
On Fri, 11 Jan 2019 00:18:28 -0500, nospam
wrote:

In article , Eric Stevens
wrote:


EV's are equivalent to stops for any purpose related to exposure.

I can change exposure value without changing the stop setting.

No ****. That's sort of the point.

It's my point. Stops aren't exposure values. Exposure values are not
stops.

they are.

Lets leave it at that.

ok, but you saying so doesn't make it correct.

Allright then. Please explain to your readers how you set a lens to an
EV of 20.

For what ISO and speed?

No, no. No ISO or speed.

Willingly obtuse.


--
"2/3 of Donald Trump's wives were immigrants. Proof that we
need immigrants to do jobs that most Americans wouldn't do."
- unknown protester

On 2019-01-11 20:41, Eric Stevens wrote:
To some photographers ... it is annoying. But it is amazing what I
have learned out of this thread.

You might want to revise that.

--
"2/3 of Donald Trump's wives were immigrants. Proof that we
need immigrants to do jobs that most Americans wouldn't do."
- unknown protester

On 2019-01-11 20:48, Eric Stevens wrote:
On Fri, 11 Jan 2019 12:47:20 -0500, Alan Browne
wrote:

On 2019-01-10 23:38, Eric Stevens wrote:
On Thu, 10 Jan 2019 07:43:24 -0500, Alan Browne
wrote:

On 2019-01-10 04:12, Eric Stevens wrote:
On Wed, 9 Jan 2019 08:36:24 -0500, Alan Browne
wrote:

Its amazing what Google can produce. This is DxO's own account of the
situation at:
https://www.dxomark.com/dxomark-came...ol-and-scores/

"Dynamic range corresponds to the ratio between the highest
brightness a camera can capture (saturation) and the lowest
brightness it can capture (which is typically when noise becomes
more important than the signal — that is, a signal-to-noise ratio
below 0 dB). A value of 12 EV is excellent, with differences below
0.5 EV usually not noticeable. Dynamic range is an open scale."

This appears to confirm that the situation is as I deduced: they are
not testing the dynamic range as recorded in a raw file. They are
testing the range that a camera can capture. i.e. it is the dynmaic
range of the sensor. It is not the dynamic range of the raw file.

It doesn't actually say that, however.

How, specifically, are they bypassing the raw file to get the data?


By measuring not the data in the file but the range of brightness that
the camera can capture from their test set up.

And where _specifically_ are they getting that data? What is the probe
point? What is the probe?

Read the URL. The use multiple light sources, each of different
calibrated illuminance. It's rather like photographing an gray-scale
wedge.

Oh. Thanks. Now it's CLEAR TO ME YOU HAVE NO CLUE.

My question related to how they measure the brightness at the camera.

And you're not replying with an answer to that. At all.

The object is the measurement of the ability of the camera to detect
both low light and bright light. To do this they get the camera to
photograph a target containg multiple light sources covering a range
of luminances. Some are too bright and the other too dark for the
camera to properly capture. It is the difference between these which
determines the dynamic range of the sensor. note that they evaluate
the DR in terms of a RGB composite analysis, the details of which I am
not aware. With this technique there is no need to measure the
brightness at the camera.

IOW: You have no clue.

Here's a clue. Where they are getting the "brightness" information at
the camera is from the camera image file. Period.

Why? Because there is no means for them to sample the sensor between
the sensor and the ADC.

Why? Because that would require a high end clean room and data that is
proprietary to the camera sensor maker.

The ONLY data they can get is from the file and the data in there is
from a 14 bit ADC. There is no more information in there than what 14
bits can hold. There may indeed be a mysterious compression as you
claim, but that has its own image quality consequences.

This has been pointed out to you several times but you seem determined
to want to believe the unbelievable ...



--
"2/3 of Donald Trump's wives were immigrants. Proof that we
need immigrants to do jobs that most Americans wouldn't do."
- unknown protester

In article , Eric Stevens
wrote:

The problem is clearly DXO's testing methods. No matter how you look
at this, you have to be able to imagine all kinds of sources of
inaccurate measurements, especially if they are slight. I have to
agree with nospam and Alan. You can't get DR outside of the limits of
the ADC because that is the output you see, but you can certainly get
test results outside of that limit.

But the digital DR of the output of the ADC is not the same as the
analog DR of the sensor. Nor is there any reason why it should be.

nobody said it was, however, it's always going to be limited by the adc.

The recorded output of the ADC is limited by the capabilities of the
ADC. But these have no effect on the capabilities of the sensor.

again, nobody said the adc would alter the sensor's capability.

You have been strenuously arguing that it will limit it.

as has everyone else, because it does.

you're confusing limiting with altering (and a lot more).

I have been
pointing out that that is not necessarily the case.

it's always the case, except perhaps with your imaginary cameras that
don't exist.

what you still fail to grasp is that whatever the sensor can produce
will always be limited by the adc, unless the sensor itself is the
limiting factor, which is not the case in a d800 class camera.

It depends by what you mean by 'limited'.

no

The sensor will always do do
whatever it can do and it's DR can be scaled up or down to fit the
output bandwidth of the ADC. It is because of the scaling that you can
have the output of a sensor with a 14.8 stop DR scaled down to to suit
a 14 bit ADC. It's not a big deal.

except that it's *not* scaled.

imaginary cameras do not count.

If
the sensor can discriminate between luminance levels from 'c' to 'q'
it will always retain that ability irrespective of the capabilities of
the ADC. How the ADC encodes it is another matter, and how that image
is decoded by RAW decoder is another matter again. There is enormous
scope for fiddling and adjustments.

except that no fiddling or adjustments are being done.

You would know that if you worked for the right section of Nikon. Or
perhaps you have reverse engineered a D800? You will also have to know
what goes on in the Nikon RAW decoder. So I don't actually believe you
know.

there is no need to work for nikon to know that the sensor directly
feeds the adc. your own links even confirmed that in a block diagram.

if this was not the case, the 'fiddling' would be well known since the
camera would perform differently than previous cameras, and it would
likely be marketed as a benefit (e.g., 'new hdr sensor'), and hotly
argued because the camera is 'not pure' or some such.

and if it really *is* the sensor they're measuring, then it should be
the *same* for the *same* sensor, and it is not.

Not when you shove another piece of glass in front of one of the
sensors.

no effect on dynamic range.

So you keep saying. That doesn't make it true.

it's true because it is true.

Nor when you realise that not all sensors will be identical
and all measurements are subject to errors.

especially when the methodology is itself an error.

How can it be an error when they make clear what they are testing and
how?

when their numbers defy physics.

if they're supposedly measuring the sensor's dynamic range, explain why
the nikon d50 & d70 differ by a half-stop, both of which used the same
popular 6mp sony sensor (as did pentax). other results also differ.

I have no way of knowing but the first thing I would suspect is the
circuitry between the sensor and the ADC.

then you'd be wrong. there is nothing between the sensor and adc, in
those two or any other camera under discussion.

Do you know whether the ADC is pipelined, or perhaps Nikon use one ADC
per column of pixels? In any case, do you know whether the voltage
divider resistors all have the same value? That the sort of thing
which Nikon's competitors would like to know. For that matter, is the
ADC the same in each camera under discussion? I'm afraid I don't share
your confidence in your certainty.

none of that is in any way relevant.

you're just spewing buzzwords hoping to fool people.

the d50 & d70 are basically the same camera, with minor feature
differences, such as the d70 having two control wheels versus one,
compact flash versus sd card, slightly faster frame rate, wired remote
option, flash commander mode and some minor other things i don't
remember, none of which have *any* effect on the dynamic range.

If you examine first
https://imaging.nikon.com/lineup/dslr/d50/index.htm and then
https://imaging.nikon.com/lineup/dslr/d70/ you will see that the D70
boasts of:

"New Nikon DX Format CCD image sensor for 3,008 x 2,000-pixel images

New advanced digital image processor to optimize image quality,
control auto white balance, auto tone and color control"

that's just marketing babble.

both cameras use the same sony 6mp sensor, which was also used in
several other cameras at the time, including the nikon d100 and d40 as
well as the horribly named pentax *ist.

I would expect the D70 and D50 to have different characteristics.

as i recall, the jpegs were slightly different at default settings, but
that's *after* the adc, it does not apply to raw images and definitely
not a factor for dynamic range of the sensor.

you are claiming the properties of the sensor is what matters, so the
same sensor would have the same properties regardless of camera. any
differences would be in the camera itself, which you are excluding.