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



 
 
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  #181  
Old January 11th 19, 05:14 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default Finally got to the point where no new camera holds my interest (waiting for specific offering)

On Thu, 10 Jan 2019 10:32:22 -0500, nospam
wrote:

In article , Eric Stevens
wrote:


This illustrates the disadvantage of not using the language with
precision. As I said, all my lenses make use of f/numbers which are a
measure of stops. Your thoughts have jumped the rails and are now
talking about the intervals of Exposure Value of which the camera is
capable. The exposure value may be used to set lens aperture, shutter
speed or ISO. They are not identical to stops.

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


I can change exposure value without changing the stop setting.


you are confusing f/stop with stop.


'stop' is an abreviated way of referring to an obsolete way of
changing lens aperture. It's use as a reference to lens aperture is
now normal.
--

Regards,

Eric Stevens
  #182  
Old January 11th 19, 05:34 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default Finally got to the point where no new camera holds my interest (waiting for specific offering)

On Thu, 10 Jan 2019 03:51:41 -0800 (PST), Whisky-dave
wrote

--- snip ---

This illustrates the disadvantage of not using the language with
precision. As I said, all my lenses make use of f/numbers which are a
measure of stops. Your thoughts have jumped the rails and are now
talking about the intervals of Exposure Value of which the camera is
capable. The exposure value may be used to set lens aperture, shutter
speed or ISO. They are not identical to stops.

they absolutely are.


So I double the shutter speed. I have halved the exposure value but I
haven't affected the stop setting.


Exposure value is really a measure of the brightness irrespective of the shutter speed or aperature. Which is why sensor can have EV values which aren;t referenced to shutter speeds or stops.

Exposure value is a measure of the total quantity of light falling on
the sensor. i.e its a function of lens aperture and length of time of
exposure.

If you look at the table here.


https://en.wikipedia.org/wiki/Exposure_value
example EV 10

10 1/1000 1/500 1/250 1/125 1/60 1/30


If you are referring to Table 1 it shows "Exposure times, in seconds
or minutes (m), for various exposure values and f-numbers"

The shutter speed columns are headed with a corresponding F number:
EV 1.0 1.4 2.0 2.8 4.0 5.6
10 1/1000 1/500 1/250 1/125 1/60 1/30

It all makes perfect sense once you take the two separate parameters
into account.

so changing the shutter speed has NO effect on the EV.


It doesn't if you make the corresponding change in the lens aperture
as well.

See up above a 1/1000 doubling that is 1/500, you can even double it again it's still the same EV value of 10


Because the aperture has gone from 1.0 to 1.4 to 2.0 respectively.

What will change is that the shutter will open for twice as long allowing more light onto the sensor or the film or even the human eye.


The shutteer will open for twice as long allowing light to fall on it
for longer. But the lens will be stopped down to halve the
illumination of the sensor. 2 x 1/2 = 1. No change.
--

Regards,

Eric Stevens
  #183  
Old January 11th 19, 05:36 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default Finally got to the point where no new camera holds my interest (waiting for specific offering)

On Thu, 10 Jan 2019 07:46:00 -0500, Alan Browne
wrote:

On 2019-01-10 04:22, Eric Stevens wrote:
On Tue, 08 Jan 2019 10:28:28 -0500, nospam
wrote:

In article , Eric Stevens
wrote:

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.

I bow to your superior knowledge of my equipment.

your equipment is nothing special. many people have the same stuff.

for modern lenses, it's user selectable at 1, 1/2 or 1/3 stops. not all
options may be available on all cameras. it appears that nikon no
longer offers 1 stop anymore (there's no reason to) but older nikon
slrs did. i assume canon, pentax, etc., are similar.

examples:
https://www.imaging-resource.com/PRODS/D7000/screens/DSC_0211.jpg
https://1.img-dpreview.com/files/p/a...ages/Captures/
d1x_41.gif
http://www.steves-digicams.com/2004_reviews/d70/d70_custom_menu2.jpg

for older lenses with a mechanical aperture ring (manual lenses and
early autofocus), the aperture ring will normally click at 1 stop
increments, sometimes 1/2 stop. occasionally, it's both on the same
lens, i.e., the widest and smallest are 1 stop, rest 1/2 stop. there is
no point in 1/3 stops since the mechanics aren't good enough.

some lenses, such as mirror lenses, have only one f/stop, with no
adjustments to be made, although they sometimes accept an nd filter in
the back.

This illustrates the disadvantage of not using the language with
precision. As I said, all my lenses make use of f/numbers which are a
measure of stops. Your thoughts have jumped the rails and are now
talking about the intervals of Exposure Value of which the camera is
capable. The exposure value may be used to set lens aperture, shutter
speed or ISO. They are not identical to stops.

they absolutely are.


So I double the shutter speed. I have halved the exposure value but I
haven't affected the stop setting.

If you want to continue arguing to the contrary I will be happy to
leave you to it.


Reciprocity games. "Introduction to photography 101."


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

Regards,

Eric Stevens
  #184  
Old January 11th 19, 05:38 AM posted to rec.photo.digital
Eric Stevens
external usenet poster
 
Posts: 13,611
Default Finally got to the point where no new camera holds my interest (waiting for specific offering)

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.
--

Regards,

Eric Stevens
  #185  
Old January 11th 19, 05:45 AM posted to rec.photo.digital
Bill W
external usenet poster
 
Posts: 1,692
Default Finally got to the point where no new camera holds my interest (waiting for specific offering)

On Fri, 11 Jan 2019 16:52:47 +1300, Eric Stevens
wrote:

On Thu, 10 Jan 2019 07:39:32 -0500, Alan Browne
wrote:

On 2019-01-10 04:05, Eric Stevens wrote:
On Tue, 8 Jan 2019 08:31:05 -0500, Alan Browne
wrote:

On 2019-01-08 03:54, Eric Stevens wrote:
On Mon, 07 Jan 2019 23:42:07 -0500, nospam
wrote:

In article , Eric Stevens
wrote:

But a moot point IMO. I doubt the sensor mentioned has
14 bits of DR in the first place. Esp. once you account for noise.

Well, DxO measure 14.3 but what exactly that means is unknown. But if
they made that specific statement then I would expect they must have
grounds.

it means their test methodology is worthless or they're intentionally
lying.

Or that you have failed to understand what they are doing.

Your other post ends with a statement to the effect that DxO don't say
what their algorithms are doing, so nospam certainly didn't fail anything.

nospam will fail to understand what they are doing if he doesn't know
what they are doing. That applies to everyone.

In the end physics is physics and there is no way they are getting more
DR than the sensor offers. Not even the bit depth of it.

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).

A 14 bit ADC can output 16,384 distinct numerical values and the
analog output of the sensor has to be mapped to this range. It doesn't
matter what the Dynamic Range of the sensor may be. It has to be
mapped to the numerical scale of the output of the ADC. It is
perfectly feasible to map an analogue dynamic range to 14 bits (o12
(or 8)). Not withstanding what else has been written in this thread
the choice of the number of bits used to encode the sensor's output
does not affect the _sensor's_ dynamic range.


But the issue is not the sensor's DR, it's the camera's DR. The output
of the camera is the output of the ADC - not the sensor, and that ADC
is limited to 14 stops as designed.

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.
  #186  
Old January 11th 19, 05:47 AM posted to rec.photo.digital
Ron C
external usenet poster
 
Posts: 415
Default Finally got to the point where no new camera holds my interest(waiting for specific offering)

On 1/10/2019 11:36 PM, Eric Stevens wrote:
On Thu, 10 Jan 2019 07:46:00 -0500, Alan Browne
wrote:

On 2019-01-10 04:22, Eric Stevens wrote:
On Tue, 08 Jan 2019 10:28:28 -0500, nospam
wrote:

In article , Eric Stevens
wrote:

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.

I bow to your superior knowledge of my equipment.

your equipment is nothing special. many people have the same stuff.

for modern lenses, it's user selectable at 1, 1/2 or 1/3 stops. not all
options may be available on all cameras. it appears that nikon no
longer offers 1 stop anymore (there's no reason to) but older nikon
slrs did. i assume canon, pentax, etc., are similar.

examples:
https://www.imaging-resource.com/PRODS/D7000/screens/DSC_0211.jpg
https://1.img-dpreview.com/files/p/a...ages/Captures/
d1x_41.gif
http://www.steves-digicams.com/2004_reviews/d70/d70_custom_menu2.jpg

for older lenses with a mechanical aperture ring (manual lenses and
early autofocus), the aperture ring will normally click at 1 stop
increments, sometimes 1/2 stop. occasionally, it's both on the same
lens, i.e., the widest and smallest are 1 stop, rest 1/2 stop. there is
no point in 1/3 stops since the mechanics aren't good enough.

some lenses, such as mirror lenses, have only one f/stop, with no
adjustments to be made, although they sometimes accept an nd filter in
the back.

This illustrates the disadvantage of not using the language with
precision. As I said, all my lenses make use of f/numbers which are a
measure of stops. Your thoughts have jumped the rails and are now
talking about the intervals of Exposure Value of which the camera is
capable. The exposure value may be used to set lens aperture, shutter
speed or ISO. They are not identical to stops.

they absolutely are.

So I double the shutter speed. I have halved the exposure value but I
haven't affected the stop setting.

If you want to continue arguing to the contrary I will be happy to
leave you to it.


Reciprocity games. "Introduction to photography 101."


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" ?
--
==
Later...
Ron C
--

  #187  
Old January 11th 19, 06:18 AM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default Finally got to the point where no new camera holds my interest (waiting for specific offering)

In article , Eric Stevens
wrote:

In the end physics is physics and there is no way they are getting more
DR than the sensor offers. Not even the bit depth of it.

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).

A 14 bit ADC can output 16,384 distinct numerical values and the
analog output of the sensor has to be mapped to this range. It doesn't
matter what the Dynamic Range of the sensor may be. It has to be
mapped to the numerical scale of the output of the ADC. It is
perfectly feasible to map an analogue dynamic range to 14 bits (o12
(or 8)). Not withstanding what else has been written in this thread
the choice of the number of bits used to encode the sensor's output
does not affect the _sensor's_ dynamic range.


the sensor's dynamic range is not what's being measured.

dxo is reporting the dynamic range of various *cameras*.

and even if you ignore the 14 bit issue, their numbers are highly
suspect.

the nikon d800 and d800 are identical cameras, the only difference
being the lack of an anti-alias filter on the d800e, something which
does not affect dynamic range (only aliasing). thus, the results should
be *the* *same* (other than alias artifacts on high frequency content).

dxo claims that the d800 has 14.4 stops dynamic range and the d800e has
14.3 stops.

other test results also differ between the two cameras. they also claim
that the d800e has a higher low light iso, again, with the same sensor,
which is *opposite* to what one would expect if it has less dynamic
range.

that alone shows something is very, very wrong with their tests, and to
your point, is *not* a measure of the sensor itself.

https://www.dxomark.com/Cameras/Nikon/D800
https://www.dxomark.com/Cameras/Nikon/D800E
  #188  
Old January 11th 19, 06:18 AM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default Finally got to the point where no new camera holds my interest (waiting for specific offering)

In article , Eric Stevens
wrote:

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,
[1] ---
or possibly very fine steps in speed priority or auto modes.

I bow to your superior knowledge of my equipment.

Do your lenses have stops?

Yes.

Exactly. So they are indeed calibrated in EV. ([1] above).

No. EVs can be deduced. See
https://en.wikipedia.org/wiki/Exposure_value

"In photography, exposure value (EV) is a number that represents a
combination of a camera's shutter speed and f-number, such that all
combinations that yield the same exposure have the same EV (for any
fixed scene luminance)."


from that link,
Exposure value is also used to indicate an interval on the
photographic exposure scale, with a difference of 1 EV corresponding
to a standard power-of-2 exposure step, commonly referred to as a
stop.

it would be wise to learn the basics of photography so that you
actually understand what it is you're reading before commenting
further.


It might be commonly referred to as a stop but that is just plain
sloppy usage.


it's not sloppy at all. in fact, it's exactly correct.

On that basis you might as well call the shutter speed a
stop or even the ISO a stop.


the *difference* is called a stop, aka 'interval on the photographic
exposure scale':
Exposure value is also used to indicate an interval on the
photographic exposure scale, with a difference of 1 EV corresponding
to a standard power-of-2 exposure step, commonly referred to as a
stop.


iso 800 is one stop more sensitive than iso 400.
1/250th is one stop less light than 1/125th.
f/4 is one stop more light than f/5.6.

I initially mentioned this topic in passing when I referred to sloppy
writing. I didn't call for examples.


unfortunately for you, examples were provided and they show that you
don't understand it.
  #189  
Old January 11th 19, 06:18 AM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default Finally got to the point where no new camera holds my interest (waiting for specific offering)

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.
  #190  
Old January 11th 19, 06:18 AM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default Finally got to the point where no new camera holds my interest (waiting for specific offering)

In article , Eric Stevens
wrote:


This illustrates the disadvantage of not using the language with
precision. As I said, all my lenses make use of f/numbers which are a
measure of stops. Your thoughts have jumped the rails and are now
talking about the intervals of Exposure Value of which the camera is
capable. The exposure value may be used to set lens aperture, shutter
speed or ISO. They are not identical to stops.

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

I can change exposure value without changing the stop setting.


you are confusing f/stop with stop.


'stop' is an abreviated way of referring to an obsolete way of
changing lens aperture. It's use as a reference to lens aperture is
now normal.


doing so is what you call 'sloppy'.

you're confusing stop, f/stop and aperture and also ev.
 




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