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

On Wed, 02 Jan 2019 08:25:37 -0500, nospam
wrote:

In article , Eric Stevens
wrote:


https://expertphotography.com/unders...hotography-exp
osure/

The author of that article is using 'stop' when he should be using
'exposure value'. But lets not get into that in this thread. It's
confused enough already. :-)

equivalent.

Did the author attend the same school of technical writing that
trained you? He starts off with "In photography, a ‘f/stop’ is a
measurement of an exposure" and then launches into "... the infamous
shutter speed, ISO or aperture settings". A really confused beginning.

f/stop is not a measurement of exposure, but of lens opening. In
combination with shutter speed lens opening gives exposure.

Then he goes and writes "So, for example, suppose your camera’s
aperture is f/4, shutter speed is 1/100 and ISO is 100. If you keep
the aperture at f/4 and the shutter speed at 1/100 but you increased
the ISO to 200, you have increased the exposure by one stop" which is
utter nonsense. Changing the ISO without changing anything else does
not affect the exposure one iota. With unchanged shutter speed and
unchanged lens opening the exposure is unchanged also.

.... and so on he goes.

Never use a correct word when you can use an uninformed substitute. It
enables you to later select the meaning which best suits your line of
argument at the moment. :-)
--

Regards,

Eric Stevens

On Sat, 5 Jan 2019 09:32:36 -0500, Alan Browne
wrote:

On 2019-01-05 05:03, Eric Stevens wrote:
rOn Thu, 3 Jan 2019 11:26:55 -0500, Alan Browne
wrote:

On 2019-01-03 10:58, Peter Irwin wrote:
nospam wrote:
In article , Peter Irwin
wrote:

the issue was that dxo claimed that several cameras which have a 14 bit
adc could produce nearly 15 stops of dynamic range.

that's not possible.

You have to give up linear encoding, but sure it is possible.
It might be perfectly sensible to have a toe and shoulder to the
curve which would allow 15 stops of dynamic range encoded in 14 bits.

I do not know if that is what is happening, but it would be a reasonable
thing to do.

A major departure from linear encoding anywhere other than the toe and
shoulder would not be a good idea.

It used to be common to assume about 1.5 bits worth of noise to any ADC
sample so you'd have to account for that (even if less than 1.5 bits
worth, noise is ... noise).

Yours is the first answer which appears to throw light on the
difference of opinion.

No. Nospam said it clearly enough: there is no magic.

s all the painfully obvious stuff


In any case it is quite possible for the dynamic range of the sensor
to exceed the dynamic range of the system of encoding.

In which case the sensor maker would have been foolish to not put in a
16 bit ADC for the case at hand. It is far more likely that the sensor
does not have the DR and that the 14 bit ADC exceeds the DR of the
sensor. That is usually the way engineers do these sorts of things[1].

It could be that Nikon did not think that the slight overflow of DR
was worth striving for (too noisy at the ends?) and in any case
already had a perfectly good 14 bit ADC. In any case we don't know (or
I don't know) how DxO either defines or measure DR. Nor do we know
what Nikon does betwee the sensor and the output of the ADC. We are up
to our necks in speculation.

"Compressing" (Stretching, really) any portion of the curve (toe and
shoulder included) means increased quantization noise, so not so sure
the alleged 15 stops would really translate well to image quality.

[1] Back in the days when ADC's were expensive devices, one would "right
size" the ADC number of bits for acceptable performance v. a cost goal.
That's not much of a consideration today at the 16 bit level if the
sensor had that sort of performance - just not at all likely.

In any case, there is no output device which can do justice to 14
stops. The image will always be compressed or clipped before viewing.
--

Regards,

Eric Stevens

In article , Eric Stevens
wrote:

The author of that article is using 'stop' when he should be using
'exposure value'. But lets not get into that in this thread. It's
confused enough already. :-)

equivalent.

Did the author attend the same school of technical writing that
trained you? He starts off with "In photography, a Œf/stop¹ is a
measurement of an exposure" and then launches into "... the infamous
shutter speed, ISO or aperture settings". A really confused beginning.

it's not confusing.

however, he did fail spelling:
Decreasing the exposure by one stop is having it.

i bet you didn't even notice that oops.

f/stop is not a measurement of exposure, but of lens opening.

true.

he is conflating f/stop with stop, but that doesn't negate what he's
saying.

In
combination with shutter speed lens opening gives exposure.
Then he goes and writes "So, for example, suppose your camera¹s
aperture is f/4, shutter speed is 1/100 and ISO is 100. If you keep
the aperture at f/4 and the shutter speed at 1/100 but you increased
the ISO to 200, you have increased the exposure by one stop" which is
utter nonsense.

it's not nonsense at all.

iso 200 is one stop faster than iso 100.

Changing the ISO without changing anything else does
not affect the exposure one iota. With unchanged shutter speed and
unchanged lens opening the exposure is unchanged also.

nope.

it's called the exposure triangle:
https://i1.wp.com/www.photoblog.com/...ads/2018/08/ex
posure-triangle-PhotoBlog.jpg
http://media.digitalcameraworld.com/...tes/123/2015/0
4/Exposure_triangle_cheat_sheet.jpg

... and so on he goes.

as do you...

Never use a correct word when you can use an uninformed substitute. It
enables you to later select the meaning which best suits your line of
argument at the moment. :-)

except that nobody is doing that.

On Sat, 05 Jan 2019 20:08:20 -0500, nospam
wrote:

In article , Eric Stevens
wrote:

The author of that article is using 'stop' when he should be using
'exposure value'. But lets not get into that in this thread. It's
confused enough already. :-)

equivalent.

Did the author attend the same school of technical writing that
trained you? He starts off with "In photography, a Œf/stop¹ is a
measurement of an exposure" and then launches into "... the infamous
shutter speed, ISO or aperture settings". A really confused beginning.

it's not confusing.

however, he did fail spelling:
Decreasing the exposure by one stop is having it.

i bet you didn't even notice that oops.

f/stop is not a measurement of exposure, but of lens opening.

true.

he is conflating f/stop with stop, but that doesn't negate what he's
saying.

In
combination with shutter speed lens opening gives exposure.
Then he goes and writes "So, for example, suppose your camera¹s
aperture is f/4, shutter speed is 1/100 and ISO is 100. If you keep
the aperture at f/4 and the shutter speed at 1/100 but you increased
the ISO to 200, you have increased the exposure by one stop" which is
utter nonsense.

it's not nonsense at all.

iso 200 is one stop faster than iso 100.

It could be, or it could be at twice the shutter speed. But in this
case he hasn't increased the exposure. All he is doing is over
exposing.

Changing the ISO without changing anything else does
not affect the exposure one iota. With unchanged shutter speed and
unchanged lens opening the exposure is unchanged also.

nope.

it's called the exposure triangle:
https://i1.wp.com/www.photoblog.com/...ads/2018/08/ex
posure-triangle-PhotoBlog.jpg
http://media.digitalcameraworld.com/...tes/123/2015/0
4/Exposure_triangle_cheat_sheet.jpg

... and so on he goes.

as do you...

Never use a correct word when you can use an uninformed substitute. It
enables you to later select the meaning which best suits your line of
argument at the moment. :-)

except that nobody is doing that.
--

Regards,

Eric Stevens

In article , Eric Stevens
wrote:

In
combination with shutter speed lens opening gives exposure.
Then he goes and writes "So, for example, suppose your camera1s
aperture is f/4, shutter speed is 1/100 and ISO is 100. If you keep
the aperture at f/4 and the shutter speed at 1/100 but you increased
the ISO to 200, you have increased the exposure by one stop" which is
utter nonsense.

it's not nonsense at all.

iso 200 is one stop faster than iso 100.

It could be,

not could be. it *is*.

or it could be at twice the shutter speed.

iso has nothing to do with shutter speed, so no.

But in this
case he hasn't increased the exposure. All he is doing is over
exposing.

no.

On 2019-01-05 19:33, Eric Stevens wrote:
On Wed, 02 Jan 2019 08:25:37 -0500, nospam
wrote:

In article , Eric Stevens
wrote:


https://expertphotography.com/unders...hotography-exp
osure/

The author of that article is using 'stop' when he should be using
'exposure value'. But lets not get into that in this thread. It's
confused enough already. :-)

equivalent.

Did the author attend the same school of technical writing that
trained you? He starts off with "In photography, a ‘f/stop’ is a
measurement of an exposure" and then launches into "... the infamous
shutter speed, ISO or aperture settings". A really confused beginning.

f/stop is not a measurement of exposure, but of lens opening. In
combination with shutter speed lens opening gives exposure.

Then he goes and writes "So, for example, suppose your camera’s
aperture is f/4, shutter speed is 1/100 and ISO is 100. If you keep
the aperture at f/4 and the shutter speed at 1/100 but you increased
the ISO to 200, you have increased the exposure by one stop" which is
utter nonsense. Changing the ISO without changing anything else does

To a photographer it is entirely correct. A physicist would say, "the
same number of photons hit the film/sensor" but a photographer will say
it exposed 1 stop more because of the increased sensitivity.

not affect the exposure one iota. With unchanged shutter speed and
unchanged lens opening the exposure is unchanged also.

... and so on he goes.

Never use a correct word when you can use an uninformed substitute. It
enables you to later select the meaning which best suits your line of
argument at the moment. :-)

I won't get into what a particular author wrote or how badly or well he
did it, but stating 100 - 200 ISO change as 1 stop more exposure is
entirely correct for a photographer.

--
"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 2019-01-05 22:59, Eric Stevens wrote:


It could be, or it could be at twice the shutter speed. But in this
case he hasn't increased the exposure. All he is doing is over
exposing.

1. You don't know his intent. Maybe 1 more stop is correct exposure for
his case.

2. How can you say "hasn't increased" but "is over exposing".

Talk about messy writing!

--
"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 2019-01-04 18:58, Eric Stevens wrote:
On Fri, 4 Jan 2019 16:16:05 -0500, Alan Browne
wrote:

On 2019-01-02 04:16, Eric Stevens wrote:
On Wed, 2 Jan 2019 07:48:13 +0000, RJH wrote:

On 02/01/2019 01:38, nospam wrote:
In article , Eric Stevens
wrote:

You are obviously wedded to 1 stop per bit. Why is that?

math.

Why for example can you not have 2 stops per bit, or pi stops per bit?
As long as you scale the entire brightness range with the available 14
stops.

because it doesn't work that way.

think about what a stop means.


FWIW, I don't follow the linearity - in fact I've often wondered why
aperture, ISO and shutter speed aren't infinitely variable, especially
with digital. This article takes me closer to understanding:

https://expertphotography.com/understanding-fstops-stops-in-photography-exposure/

The author of that article is using 'stop' when he should be using
'exposure value'. But lets not get into that in this thread. It's
confused enough already. :-)

There is no difference at all between an EV and a stop of any of the
three independent variables of ISO, exposure period and aperture.

It may be hair-splitting but none of my lenses are calibrated in EVs.

They most definitely are, and probably 1/2 or 1/3 steps of EV as well,
or possibly very fine steps in speed priority or auto modes.


--
"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 2019-01-04 18:55, Eric Stevens wrote:
On Fri, 4 Jan 2019 23:04:58 -0000 (UTC), Peter Irwin
wrote:

Eric Stevens wrote:

You really should have linear encoding, but there is no reason why the
encoded range should be anything in particular.

If you have linear encoding you need twice as many numbers every
time you add a stop (which doubles the range in linear terms).
Doubling the numbers available in binary means using one more bit.

Therefore in linear terms 1 bit = 1 stop.

Peter.

That is certainly the case once the image is out in the open world.
But within the camera, in the process of transforming the sensor's
output into 12 or 14 (or any other) number of bits the camera maker is
free to select the dynamic range of their choice. They can then slice
that up to any preferred number of slices for coding.

That is the point I have been trying to make. Nikon are free to do
what they like with the image before they code it. They camera could
easily have a dynamic range of 14.3 (or whatever you like) in the
sense that it is able to discriminate across that range of light. This
is quite a separate question from how this dynamic range can be
encoded for recording on a SV card (or whatever).

See my other reply to you wrt to how engineers select ADC's for a
system; and other posts where any "coding" to "get" something somewhere
inevitably results in quantization noise (quality loss) elsewhere.

So, for your 14.3 DR above, cramming that into 14 bits has to lose
something in the information. There is no magic coding.

That isn't to say that compromise cannot be made, indeed that's a good
thing if the resulting images are better looking. But subjectively
better looking images does not equate to more DR.

TANSTAAFL.

--
"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 2019-01-05 19:55, Eric Stevens wrote:
On Sat, 5 Jan 2019 09:32:36 -0500, Alan Browne
wrote:

On 2019-01-05 05:03, Eric Stevens wrote:
rOn Thu, 3 Jan 2019 11:26:55 -0500, Alan Browne
wrote:

On 2019-01-03 10:58, Peter Irwin wrote:
nospam wrote:
In article , Peter Irwin
wrote:

the issue was that dxo claimed that several cameras which have a 14 bit
adc could produce nearly 15 stops of dynamic range.

that's not possible.

You have to give up linear encoding, but sure it is possible.
It might be perfectly sensible to have a toe and shoulder to the
curve which would allow 15 stops of dynamic range encoded in 14 bits.

I do not know if that is what is happening, but it would be a reasonable
thing to do.

A major departure from linear encoding anywhere other than the toe and
shoulder would not be a good idea.

It used to be common to assume about 1.5 bits worth of noise to any ADC
sample so you'd have to account for that (even if less than 1.5 bits
worth, noise is ... noise).

Yours is the first answer which appears to throw light on the
difference of opinion.

No. Nospam said it clearly enough: there is no magic.

s all the painfully obvious stuff


In any case it is quite possible for the dynamic range of the sensor
to exceed the dynamic range of the system of encoding.

In which case the sensor maker would have been foolish to not put in a
16 bit ADC for the case at hand. It is far more likely that the sensor
does not have the DR and that the 14 bit ADC exceeds the DR of the
sensor. That is usually the way engineers do these sorts of things[1].

It could be that Nikon did not think that the slight overflow of DR
was worth striving for (too noisy at the ends?) and in any case
already had a perfectly good 14 bit ADC. In any case we don't know (or
I don't know) how DxO either defines or measure DR. Nor do we know
what Nikon does betwee the sensor and the output of the ADC. We are up
to our necks in speculation.

That 14 bits cannot yield 15 bits of DR is not speculation.
That the bottom bit or so of information from the sensor is rot, is not
speculation.

(I'd like to know how DxO's tests treat noise in the DR calculation.
Classically the DR should include noise as a denominator thereby
reducing the DR value further as noise increases).

"Compressing" (Stretching, really) any portion of the curve (toe and
shoulder included) means increased quantization noise, so not so sure
the alleged 15 stops would really translate well to image quality.

[1] Back in the days when ADC's were expensive devices, one would "right
size" the ADC number of bits for acceptable performance v. a cost goal.
That's not much of a consideration today at the 16 bit level if the
sensor had that sort of performance - just not at all likely.

In any case, there is no output device which can do justice to 14
stops. The image will always be compressed or clipped before viewing.

It still gives the photo "editor" more information to work with. How he
uses that to improve the overall image is his choice.

--
"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