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The base ("native") ISO of a sensor



 
 
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  #31  
Old May 29th 17, 10:10 PM posted to rec.photo.digital
Floyd L. Davidson
external usenet poster
 
Posts: 5,138
Default The base ("native") ISO of a sensor

Alfred Molon wrote:
In article , Floyd L. Davidson says...

Alfred Molon wrote:
Once again: explain why at ISO 64 the exposure time is THREE times the
exposure time at ISO 200.

The DXOMark site you are referring to claims that both at ISO 64 and ISO
200 the real ISO is 83.

But if the real ISOs at ISO 64 and 200 really both were 83, the exposure
times should be the same. They are not, so DXOMark and you are wrong.


You don't understand sensor characteristics, ISO, or
exposure; and should not be saying others are wrong.

DXOMark is not wrong.

Consider that the design target for maximum output from
a sensor, in terms of linearity, may not be the actual
maximum output. Also consider that a "correct" exposure
level might be 2.7 fstops below whatever is chosen as
the "maximum output", or it might be 1.3 fstops! All of
that is totally independent of when whites actually do
clip, which is a function of the ADC, not the sensor.

And all of that makes what you believe to be how it
works just a little bit the other side of a fantasy too.


Floyd,

please explain why at ISO 64 the exposure time is three times the
exposure time at ISO 200. DXOMark claims that at both ISO settings the
true ISO is 83.


For the reasons already stated above!

--
Floyd L. Davidson http://www.apaflo.com/
Utqiagvik (Barrow, Alaska)
  #32  
Old May 30th 17, 06:37 PM posted to rec.photo.digital
Alfred Molon[_4_]
external usenet poster
 
Posts: 2,591
Default The base ("native") ISO of a sensor

In article , Floyd L. Davidson says...

Alfred Molon wrote:
In article , Floyd L. Davidson says...

Alfred Molon wrote:
Once again: explain why at ISO 64 the exposure time is THREE times the
exposure time at ISO 200.

The DXOMark site you are referring to claims that both at ISO 64 and ISO
200 the real ISO is 83.

But if the real ISOs at ISO 64 and 200 really both were 83, the exposure
times should be the same. They are not, so DXOMark and you are wrong.

You don't understand sensor characteristics, ISO, or
exposure; and should not be saying others are wrong.

DXOMark is not wrong.

Consider that the design target for maximum output from
a sensor, in terms of linearity, may not be the actual
maximum output. Also consider that a "correct" exposure
level might be 2.7 fstops below whatever is chosen as
the "maximum output", or it might be 1.3 fstops! All of
that is totally independent of when whites actually do
clip, which is a function of the ADC, not the sensor.

And all of that makes what you believe to be how it
works just a little bit the other side of a fantasy too.


Floyd,

please explain why at ISO 64 the exposure time is three times the
exposure time at ISO 200. DXOMark claims that at both ISO settings the
true ISO is 83.


For the reasons already stated above!


Again a non-answer to a simple question.

The claim was made that the ISO 3200 of the E-M1 II is not a real ISO
3200, and to back up this claim the data on DXOMark was referenced.

But this DXOMark data is obviously wrong - DXOMark measure the same ISO
83 at both ISO 64 and ISO 200, when in reality the exposure times are
vastly different.
--
Alfred Molon

Olympus E-series DSLRs and micro 4/3 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site
  #33  
Old May 30th 17, 07:00 PM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default The base ("native") ISO of a sensor

In article ,
Alfred Molon wrote:

In article , Floyd L. Davidson says...

Alfred Molon wrote:
In article , Floyd L. Davidson says...

Alfred Molon wrote:
Once again: explain why at ISO 64 the exposure time is THREE times the
exposure time at ISO 200.

The DXOMark site you are referring to claims that both at ISO 64 and ISO
200 the real ISO is 83.

But if the real ISOs at ISO 64 and 200 really both were 83, the exposure
times should be the same. They are not, so DXOMark and you are wrong.

You don't understand sensor characteristics, ISO, or
exposure; and should not be saying others are wrong.

DXOMark is not wrong.

Consider that the design target for maximum output from
a sensor, in terms of linearity, may not be the actual
maximum output. Also consider that a "correct" exposure
level might be 2.7 fstops below whatever is chosen as
the "maximum output", or it might be 1.3 fstops! All of
that is totally independent of when whites actually do
clip, which is a function of the ADC, not the sensor.

And all of that makes what you believe to be how it
works just a little bit the other side of a fantasy too.

Floyd,

please explain why at ISO 64 the exposure time is three times the
exposure time at ISO 200. DXOMark claims that at both ISO settings the
true ISO is 83.


For the reasons already stated above!


Again a non-answer to a simple question.

The claim was made that the ISO 3200 of the E-M1 II is not a real ISO
3200, and to back up this claim the data on DXOMark was referenced.

But this DXOMark data is obviously wrong - DXOMark measure the same ISO
83 at both ISO 64 and ISO 200, when in reality the exposure times are
vastly different.


Extended low ISO are been explained to you earlier in this thread. You
just don't want hear nor learn. mFT sensors are silly small only a
quarter of the size of fullframe ones. It's close to fraud comparing
them... Bigger is better! :-ppp
--
teleportation kills
  #34  
Old May 30th 17, 07:19 PM posted to rec.photo.digital
nap
external usenet poster
 
Posts: 3
Default The base ("native") ISO of a sensor

In article , Me wrote:
[ ... ]
You don't believe that if something tests better than the laws of
physics dictate is possible, then some trickery or deception is going on?
Sure it could be "error" by the manufacturer - but they seem to always
err on the side of making the camera seem to perform better than it
really does rather than worse - it is deliberate.
In the link I posted above, then the plot for "ideal 4/3" format assumes
that every pixel is captured and recorded and there's no read noise /
electronic noise degrading the dynamic range. Yet that camera appears
to perform better than is possible - better than "ideal".

The loss of dynamic range as ISO increases is inevitable "shot noise" -
there's nothing that can be done to avoid it.


Olympus and Fuji are nortorious for cheating with ISO:

http://www.photonstophotos.net/Chart...M1%20Mark%20II
  #35  
Old May 30th 17, 08:24 PM posted to rec.photo.digital
Savageduck[_3_]
external usenet poster
 
Posts: 16,487
Default The base ("native") ISO of a sensor

On 2017-05-30 18:19:55 +0000, nap said:

In article , Me wrote:
[ ... ]
You don't believe that if something tests better than the laws of
physics dictate is possible, then some trickery or deception is going on?
Sure it could be "error" by the manufacturer - but they seem to always
err on the side of making the camera seem to perform better than it
really does rather than worse - it is deliberate.
In the link I posted above, then the plot for "ideal 4/3" format assumes
that every pixel is captured and recorded and there's no read noise /
electronic noise degrading the dynamic range. Yet that camera appears
to perform better than is possible - better than "ideal".

The loss of dynamic range as ISO increases is inevitable "shot noise" -
there's nothing that can be done to avoid it.


Olympus and Fuji are nortorious for cheating with ISO:

http://www.photonstophotos.net/Chart...M1%20Mark%20II


The

issue I find disturbing is those DxOMark ISO numbers are all over the
place, and not just problematic in the areas of extended ISO.

Then there is your tagging Fujifilm in this group of questionable ISO
numbers. It is worth noting that the last Fujifilm camera evaluated was
the X100 which is the last of the Fujifilm CMOS sensored cameras. None
of the current, or recently aged, X-Trans, X-Trans II, or X-Trans III
sensored Fujifilm X-Series cameras have been evaluated by DxOMark.

There has yet to be any sort of report regarding where the current crop
of Fujifilm X-trans sensored cameras (X100S, X100T, X100F, X-Pro1,
X-Pro2, X-E1, X-E2(s), X-T1, X-T2, X-T10, or X-T20 are regarding proven
ISO ratings which might, or might not support your accusation of ISO
cheating. Unless you are aware of another lab testing sensor ISO
performance that we are not aware of. If that is the case please cite.


--
Regards,

Savageduck

  #36  
Old May 31st 17, 06:24 PM posted to rec.photo.digital
Alfred Molon[_4_]
external usenet poster
 
Posts: 2,591
Default The base ("native") ISO of a sensor

In article , nap says...
http://www.photonstophotos.net/Chart...M1%20Mark%20II


ISO 83 measured at both ISO 64 and ISO 200.

But in reality the exposure time at ISO 64 is three times the exposure
time at ISO 200. That diagram contains wrong data.
--
Alfred Molon

Olympus E-series DSLRs and micro 4/3 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site
  #37  
Old May 31st 17, 09:22 PM posted to rec.photo.digital
Floyd L. Davidson
external usenet poster
 
Posts: 5,138
Default The base ("native") ISO of a sensor

Alfred Molon wrote:
In article , nap says...
http://www.photonstophotos.net/Chart...M1%20Mark%20II


ISO 83 measured at both ISO 64 and ISO 200.

But in reality the exposure time at ISO 64 is three times the exposure
time at ISO 200. That diagram contains wrong data.
--
Alfred Molon

Olympus E-series DSLRs and micro 4/3 forum at
http://tech.groups.yahoo.com/group/M...myolympus.org/ photo sharing site


It does not.

You don't appear to be able to comprehend sensor
characteristics, ISO specifications, ISO gain, ADC
characteristics and how they relate to each other and to
SNR or Dynamic Range. You have a rigid fixed idea of
relationships that in fact are not fixed at all.

If that is not within your grasp you will just have to
accept the word others who do understand it and tell
you the chart is accurate. Rest assured that both Bill
Claff and DXOMark understand it well!

--
Floyd L. Davidson http://www.apaflo.com/
Utqiagvik (Barrow, Alaska)
  #38  
Old June 1st 17, 09:14 PM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default The base ("native") ISO of a sensor

In article 2017053012243459901-savageduck1@REMOVESPAMmecom,
Savageduck wrote:

On 2017-05-30 18:19:55 +0000, nap said:

In article , Me
wrote:
[ ... ]
You don't believe that if something tests better than the laws of
physics dictate is possible, then some trickery or deception is going on?
Sure it could be "error" by the manufacturer - but they seem to always
err on the side of making the camera seem to perform better than it
really does rather than worse - it is deliberate.
In the link I posted above, then the plot for "ideal 4/3" format assumes
that every pixel is captured and recorded and there's no read noise /
electronic noise degrading the dynamic range. Yet that camera appears
to perform better than is possible - better than "ideal".

The loss of dynamic range as ISO increases is inevitable "shot noise" -
there's nothing that can be done to avoid it.


Olympus and Fuji are nortorious for cheating with ISO:

http://www.photonstophotos.net/Chart...%20OM-D%20E-M1
%20Mark%20II


The

issue I find disturbing is those DxOMark ISO numbers are all over the
place, and not just problematic in the areas of extended ISO.

Then there is your tagging Fujifilm in this group of questionable ISO
numbers. It is worth noting that the last Fujifilm camera evaluated was
the X100 which is the last of the Fujifilm CMOS sensored cameras. None
of the current, or recently aged, X-Trans, X-Trans II, or X-Trans III
sensored Fujifilm X-Series cameras have been evaluated by DxOMark.

There has yet to be any sort of report regarding where the current crop
of Fujifilm X-trans sensored cameras (X100S, X100T, X100F, X-Pro1,
X-Pro2, X-E1, X-E2(s), X-T1, X-T2, X-T10, or X-T20 are regarding proven
ISO ratings which might, or might not support your accusation of ISO
cheating. Unless you are aware of another lab testing sensor ISO
performance that we are not aware of. If that is the case please cite.


The conclusions are for you to make...

http://www.photonstophotos.net/Chart...%20EOS%205D%20
Mark%20IV,FujiFilm%20X-T2,Olympus%20OM-D%20E-M1%20Mark%20II,Sony%20ILCE-7
RM2

http://www.photonstophotos.net/Chart...205D%20Mark%20
IV,FujiFilm%20X-T2,Olympus%20OM-D%20E-M1%20Mark%20II,Sony%20ILCE-7RM2

You should notice, however the foot and shoulder of the curves...

I'm kinda busy right now so don't expect prompt comments.
--
teleportation kills
 




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