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

On Sat, 12 Jan 2019 22:05:04 -0500, Ron C wrote:

On 1/12/2019 9:52 PM, Eric Stevens wrote:
On Sat, 12 Jan 2019 09:33:13 -0500, Alan Browne
wrote:

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.

I think that applies to all parties in this argument.


Captain: ... What we've got here is failure to communicate. Some men
you just can't reach.
[ Cool Hand Luke ]

And others resist being reached.
--

Regards,

Eric Stevens

On Thu, 10 Jan 2019 23:47:23 -0500, Ron C wrote:

You are still missing the point: lens aperture, shutter speeds or ISOs
are not identical to stops.

At this point my old physics professor would ask for dimensional analysis.
What's the dimensional analysis of "EV" vs "stop" ?

First define a stop. If you mean f-number, a stop is dimensionless.

If you mean sqrt(2) a stop is dimensionless.

If you mean 1/sqrt(2) a stop is still dimensionless.

Basically EV = Constant, or

(Shutter Speed) x f-number = another constant.
The dimensions of (Shutter Speed) are 1/T, f-number is dimensionless,
so the dimensions of EV should be 1/T.
In other words we must take language seriously.
Imprecise language discloses the lack of precision of thought."
--

On Sun, 13 Jan 2019 16:39:09 +1300, Eric Stevens
wrote:


--- snip ---

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.

I wish you wouldn't insist to that effect. I know and understand what
is going on. My problem is trying to explain it without the use of
diagrams.

I will give it one more try.

All that the ADC is doing is digitizing the level of charge which has
accumulated in the sensor cells. It does not need to know, nor would
it care, how much exposure to light that represents. Hook it up to a
sensor and a 14-bit ADC will give you a 14-bit datastream which will
tell you all about the charge and nothing about the anount of light
which has fallen on the individual cells. As far as the ADC is
concerned, the important thing is whether or not the maximum voltage
of the charges to which it is exposed is within the ADC's input range.
If it is the ADC will digitize it. How much light it required does not
matter. The ADC will as happily digitize 2 levels of charge as it will
20,000 levels of charge. No matter what it digitizes it will output a
14-bit data stream. THat's why it won't care whether it is digitizing
a collection of charges with a dynamic range of 5 or 50. All will be
OK as long as the peak is within the range of the ADC's input.
--

Regards,

Eric Stevens

In article .com,
Savageduck wrote:

After 313 posts to this mind numbing thread without any end in sight, can you
guys just pick up your cameras, and shoot something, anything?

last night i did exactly that, and probably again tomorrow.

In article , Eric Stevens
wrote:

Of course it is, unless the AA filter has none. The light which
determines the RGB image has to bass through the filter and some must
be lost on the way.

the only thing that's lost is *spatial* *detail* above nyquist (and a
little below since this is the real world).

below nyquist, there is no effect, and a grey card or other test target
has essentially no detail, so it's *well* below nyquist.

if they were shooting resolution test charts or scenes with fine
detail, there would be a difference, as one would expect, but they're
not, at least not in this test.

All of this is irrelevant. The point is no solid is perfectly
transparent. Certainly the material of the AA filter will not be.

it's close enough that it doesn't make a difference below nyquist.

So you are now arguing that the AA filter will pass all frequencies of
the electromagnetic spectrum with equal facility?

no.

read it again, this time for comprehension.

In article , Eric Stevens
wrote:

The fstop is [Image distance]/lens aperture.

also wrong. f/stop = focal length/aperture.

Aha! Your correction of me is an approximation.

it's not in any way an approximation.

See
https://en.wikipedia.org/wiki/F-number

from that link,
The f-number of an optical system (such as a camera lens) is the
ratio of the system's focal length to the diameter of the entrance
pupil.

exactly what i said it is.

"... as one focuses closer, the lens' effective aperture becomes
smaller, making the exposure darker. The working f-number is often
described in photography as the f-number corrected for lens
extensions by a bellows factor. This is of particular importance in
macro photography".

selective snipping. that's *not* cool.

Do you think I should not have snipped the several thousand irrelevant
words, tables and images between the two parts I quoted? At least I
marked that I snipped.

your snipping altered its meaning.

The several thousand words, tables and images between the two parts I
quoted contained a great deal of irrelevant meaning. That's why I
snipped them.

nope.

*one* paragraph prior to what you quoted, in the *same* section, states
that the limitation is *ignored*.

that's not even 100 words, let alone 'several thousand', without any
tables or images in between either.

https://en.wikipedia.org/wiki/F-number#Working_f-number
The f-number accurately describes the light-gathering ability of a
lens only for objects an infinite distance away.[16] This limitation
is typically ignored in photography, where f-number is often used
regardless of the distance to the object.

since you somehow missed the first few times, note this part:
This limitation is typically ignored in photography, where f-number
is often used regardless of the distance to the object.

you also mistakenly claimed that f/stop is an approximation. it is not,
which *your* link confirms, earlier in the link:
The f-number of an optical system (such as a camera lens) is the
ratio of the system's focal length to the diameter of the entrance
pupil.

it's no wonder you snipped so much. it all proves you wrong.

In article , Eric Stevens
wrote:

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.

that would be a flaw in their testing.

Yep. Which is one of the reasons that DxO do it the way they do.

no.

In article , Eric Stevens
wrote:

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.

as i said, you don't understand it.

here's a hint:
what's the difference between f/8 and f/11 ?

You are fortunate. I happen to have a lens on my desk. I've just
measured the difference is about 4mm.

good work!

since we now know that 1ev = 4mm, it's a very simple calculation to set
a lens to your desired ev 20:
simply zoom the lens to 80mm, or alternately, choose a fixed focal
length 80mm lens.

Oh no. You have it wrong. It's 4mm netween the f/8 mark and the f/11
mark on the lens ring. The diameter of the lens ring is 60mm which
gives it a circumference of 188mm. using your calculatios, 8omm is 152
degrees of rotation of the ring. I've just tried that but the ring
won't rotate that much so I have concluded that my 105mm Micro Nikkor
will not do an EV of 20.

so you're saying your initial measurements are wrong.

math is fun.

Especially when it is disconnected from reality.

then you should enjoy it more than most.

In article , Eric Stevens
wrote:


You are still missing the point: lens aperture, shutter speeds or ISOs
are not identical to stops.

At this point my old physics professor would ask for dimensional analysis.
What's the dimensional analysis of "EV" vs "stop" ?

First define a stop.

use the standard definition.

If you mean f-number, a stop is dimensionless.

stop and f/stop are not the same.

If you mean sqrt(2) a stop is dimensionless.

If you mean 1/sqrt(2) a stop is still dimensionless.

Basically EV = Constant, or

(Shutter Speed) x f-number = another constant.
The dimensions of (Shutter Speed) are 1/T, f-number is dimensionless,
so the dimensions of EV should be 1/T.

nope.

In other words we must take language seriously.
Imprecise language discloses the lack of precision of thought."

yep.

In article , Eric Stevens
wrote:


A meat grinder will alter a sheep. But before the grinder the sheep
will remain a sheep and after the grinder the sheep will be whatever
the grinder produces. If you are going to determine the height of a
sheep would you prefer to do it before or after the grinder?

it's entirely irrelevant, in every possible way.

it's also not correct. the sheep cease to be sheep well before it
reaches the meat grinder.

Oh no. In my example the sheep are thrown straight into the meat
grinder.

that's going to make for some very unpalatable meat, one reason of many
why your example is both irrelevant and absurd.

In any case: it's not irellevant.

it is, and absurd too.

You will argue that this is irellevant, but it's not.

it is. very much so.

It's an analogy.

a bad one. horrible and nonsensical.

The place to
measure the DR of a sensor is at the sensor and not at the output of
an ADC. DxO's method measures the DR at the sensor.

only for those designing cameras and sensors, and it doesn't.
for *everyone* else (including you, since you don't do either of
those), the place to measure dynamic range are from *the* *images*,
which means after the adc + isp + anything else in the image path.

Well DxO have explained what they are doing (quite clearly I would
have thought) and they are measuring it at the sensor. You should
write to them and explain they have got it wrong. No ordinary
photographer is interested in the DR of the sensor.

exactly. photographers are interested in the dynamic range of the
camera, which is one reason why what dxo is doing is bogus.

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.

Of course it is. In any sensible design the DR of the input to the ADC
will be designed to accept the DR of the sensor's output.

actually, the adc will be designed to match that of the sensor's
capabilities.

I'm glad we have agreed on that. So now we go from transforming the
number of electrons in each light well into a binary representation
using 14 bit. I have called this process scaling. I would like to know
what you call it.

what any ee would call it, quantization.

it's definitely not scaling.

if this was not the case, the 'fiddling' would be well known since the
camera would perform differently than previous cameras, ...

But they do, they do

no they don't. they perform as expected.

Better and better with each new model in a series. Are you claiming
this is not behaving differently?

except that it's consistent with the normal progress of technology,
nothing out of the ordinary.

on the other hand, if a new camera doubled the dynamic range of its
predecessor, that would be well outside the norm, suggesting there's
some fiddling going on.

there are no breakthroughs other than computationally, such as google
night sight, which has nothing to do with the sensor technology or adc.

... 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.

It is merely your assumption that every individual design advance
would be trumpeted by the marketing department.

of course they will. it's a competitive advantage over the other
products.

There are probably hundreds of improvements in each new design. You
can't expect them to extoll them all.

nobody said all of them, but they will very definitely hype the major
ones to set it apart from the competition.

a dramatic increase in dynamic range due to some sort of preprocessing
would be that.

Besides, there are some they may
not want to bring to the attention of the opposition.

oh, they know, and they'll reverse engineer it if they have to.

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.

No glass (or in this case the material of the AA filter) offers 100%
transmissability to the electromagnetic spectrum. You continuing to
argue otherwise is plain silly.

you're really grasping at straws now.

nobody said 100%.

You implied 100% when you denied that the AA filter would have any
affect on the light falling on the sensor.

you're seriously grasping at straws.

look out your window, both with the window closed (through the glass)
and with it open (no glass).

do you notice a difference in dynamic range, colour balance, amount of
detail, etc? no.




But,
nevertheless, I would be surprised if 16 months of development did not
result in the slight improvement of the sensor DR range shown by the
D50.

except that your claim is that dxo measures the sensor, not the camera,
so if both have the same sensor, the dynamic range would be the same.

at least try to be consistent.

But 16 months later, do they both have the same sensor?

yes, as did many other cameras at the time.

also, the d50 and d70s came out at the same time, so any supposed
improvement would be in *both* cameras, yet there's a difference.

https://www.dxomark.com/Cameras/Nikon/D50
https://www.dxomark.com/Cameras/Nikon/D70s

The dates of release are listed in
https://en.wikipedia.org/wiki/Nikon#...ompact_cameras

€ Nikon D50, April 20, 2005 - Discontinued
€ Nikon D70S, April 20, 2005 - Discontinued

perhaps you use a different calendar than the rest of the world, but
where i come from, that's what is known as 'at the same time'.

In any case, arguing with you is leaving a foul taste in my mouth.
This is more than enough.

only because you've been eating meat ground from whole sheep. nobody
wants to eat wooly meat. blech.