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The base ("native") ISO of a sensor



 
 
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  #11  
Old May 27th 17, 01:24 AM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default The base ("native") ISO of a sensor

In article ,
RichA wrote:

The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a bit
less dynamic range) but the highest dynamic range at ISO 200. So what
would be the native or base ISO of the sensor?
How would that be defined?

The "base" would be the ISO where the analog and digital gain are both 1
(0 dB). I've never seen a camera maker publish that. The analog gain
stage is a noise source in itself - even at 0 dB - but unavoidable.

For my cameras (DSLR's) the base appears to be ISO 160 based on various
noise graphs. But frankly anywhere from 100 to 400 appears the same in
normal viewing. 800 and shadow noise is discernible in processing at
100% zoom but invisible in prints or display.


Although this post disputes what I wrote above - a lot to learn there.

http://www.clarkvision.com/articles/....summary/#unit
y_gain


One post here (by a noted astronomical CCD camera expert) says there is no
such thing as native ISO because there is amplification at every ISO.

http://www.tomsguide.com/forum/30791...-native-sensor


that's a thread from this newsgroup and the ccd camera expert is roger
clark, who used to post here and owns clarkvision.com and authored the
previous link.
  #12  
Old May 27th 17, 03:54 AM posted to rec.photo.digital
Me
external usenet poster
 
Posts: 470
Default The base ("native") ISO of a sensor

On 27/05/2017 6:32 AM, Alfred Molon wrote:
In article , Me says...

On 26/05/2017 5:50 PM, nospam wrote:
In article , Sandman
wrote:

The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a bit
less dynamic range) but the highest dynamic range at ISO 200. So what
would be the native or base ISO of the sensor?
How would that be defined?

Unless the camera maker doesn't specify this specifically, there is no way
to know when the sensor output is boosted or not.

there is.

Yes.
and also the comment that:
"The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a
bit less dynamic range)
makes no sense.

Anyway, as Scotty said - "Ye cannae change laws of physics"

http://photonstophotos.net/Charts/PD...M1%20Mark%20II
But wait - Olympus appears to have done so.
So either they're bull****ting about actual ISO setting (which they've
done before) or bull****ting by applying noise reduction to raw files
(which they've also done before), or bull****ting about both (likely).
So if you /think/ when it's set at ISO 6400 - it actually is, and you
/think/ there's no NR applied to raw files, and are happy with the
result, then enjoy.


... what have you been smoking?

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.
  #13  
Old May 27th 17, 04:09 AM posted to rec.photo.digital
Me
external usenet poster
 
Posts: 470
Default The base ("native") ISO of a sensor

On 27/05/2017 2:54 PM, Me wrote:
On 27/05/2017 6:32 AM, Alfred Molon wrote:
In article , Me says...

On 26/05/2017 5:50 PM, nospam wrote:
In article , Sandman
wrote:

The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of
a bit
less dynamic range) but the highest dynamic range at ISO 200. So what
would be the native or base ISO of the sensor?
How would that be defined?

Unless the camera maker doesn't specify this specifically, there is
no way
to know when the sensor output is boosted or not.

there is.

Yes.
and also the comment that:
"The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a
bit less dynamic range)
makes no sense.

Anyway, as Scotty said - "Ye cannae change laws of physics"

http://photonstophotos.net/Charts/PD...M1%20Mark%20II

But wait - Olympus appears to have done so.
So either they're bull****ting about actual ISO setting (which they've
done before) or bull****ting by applying noise reduction to raw files
(which they've also done before), or bull****ting about both (likely).
So if you /think/ when it's set at ISO 6400 - it actually is, and you
/think/ there's no NR applied to raw files, and are happy with the
result, then enjoy.


... what have you been smoking?

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.


Oh nice.
Bill Claff has produced an interactive chart showing comparison between
set ISO and measured ISO.
Olympus OMD E1 MkII overstates real ISO by 1.23 stops!
Something many fanboys won't want to accept I guess - those ISO3200
shots are actually only ISO 1365 - LOL.
He's also measured base/native ISO is ISO 200.
http://photonstophotos.net/Charts/Measured_ISO.htm

  #14  
Old May 27th 17, 06:19 AM posted to rec.photo.digital
Alfred Molon[_4_]
external usenet poster
 
Posts: 2,591
Default The base ("native") ISO of a sensor

In article , Me says...
Oh nice.
Bill Claff has produced an interactive chart showing comparison between
set ISO and measured ISO.
Olympus OMD E1 MkII overstates real ISO by 1.23 stops!
Something many fanboys won't want to accept I guess - those ISO3200
shots are actually only ISO 1365 - LOL.
He's also measured base/native ISO is ISO 200.
http://photonstophotos.net/Charts/Measured_ISO.htm


He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II.
But the exposure time at ISO 64 is three times longer than at ISO 200,
so clearly this Bill Claff is wrong.
--
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
  #15  
Old May 27th 17, 08:40 AM posted to rec.photo.digital
Me
external usenet poster
 
Posts: 470
Default The base ("native") ISO of a sensor

On 27/05/2017 5:19 PM, Alfred Molon wrote:
In article , Me says...
Oh nice.
Bill Claff has produced an interactive chart showing comparison between
set ISO and measured ISO.
Olympus OMD E1 MkII overstates real ISO by 1.23 stops!
Something many fanboys won't want to accept I guess - those ISO3200
shots are actually only ISO 1365 - LOL.
He's also measured base/native ISO is ISO 200.
http://photonstophotos.net/Charts/Measured_ISO.htm


He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II.
But the exposure time at ISO 64 is three times longer than at ISO 200,
so clearly this Bill Claff is wrong.

DXO say the same, so no, Bill Claff is not wrong:
https://www.dxomark.com/Cameras/Comp..._1136_1070_909
Olympus lie about ISO. Big lies - Trump style lies.
  #16  
Old May 27th 17, 02:31 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 , Me says...

On 27/05/2017 5:19 PM, Alfred Molon wrote:
In article , Me says...
Oh nice.
Bill Claff has produced an interactive chart showing comparison between
set ISO and measured ISO.
Olympus OMD E1 MkII overstates real ISO by 1.23 stops!
Something many fanboys won't want to accept I guess - those ISO3200
shots are actually only ISO 1365 - LOL.
He's also measured base/native ISO is ISO 200.
http://photonstophotos.net/Charts/Measured_ISO.htm


He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II.
But the exposure time at ISO 64 is three times longer than at ISO 200,
so clearly this Bill Claff is wrong.

DXO say the same, so no, Bill Claff is not wrong:
https://www.dxomark.com/Cameras/Comp..._1136_1070_909
Olympus lie about ISO. Big lies - Trump style lies.


No.

If the exposure time at ISO 64 is *three times* the exposure time at ISO
200, then both ISO settings do not have the same "true ISO" of 83.

That is a *fact* and if DXOMark or whoever say otherwise, they are
wrong.
--
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
  #17  
Old May 28th 17, 05:51 AM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default The base ("native") ISO of a sensor

In article ,
RichA wrote:

On Friday, 26 May 2017 00:08:58 UTC-4, android wrote:
In article ,
RichA wrote:

On Thursday, 25 May 2017 18:03:37 UTC-4, Alfred Molon wrote:
The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a
bit
less dynamic range) but the highest dynamic range at ISO 200. So what
would be the native or base ISO of the sensor?
How would that be defined?
--
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

Nobody knows. Finding a place where it is pinned-down to a specific
sensor
is difficult. Likely you'd have better luck finding out in a
professional
area where CCD and CMOS-based cameras actually have to meet certain
specs,
unlike the consumer realm.


As we all know: The sensors of quarterframe/mFT cameras are silly small.
Thus the photon wells are small too! At the lower ISO the wells fills up
more and thus the noise is reduced but the room for play at the top of
the well gets thiner and then again less dynamic range is found in the
files.

Again: Bigger is better! :-))
--
teleportation kills


And yet...the 36mp FF sensor has the same pixel well-depth as an old 10mp
m4/3rds sensor, but no one criticized the D800...


https://www.dxomark.com/Cameras/Comp...us-OM-D-E-M1-M
ark-II-versus-Canon-EOS-5D-Mark-IV-versus-Nikon-D810___1136_1106_963

Go to the tab "Measurements" and then "Dynamic Range"...

You see Olympus quaterframe sensor wells are about half the size of the
full frames Nikon and Canons despite their almost double resolution...
--
teleportation kills
  #18  
Old May 28th 17, 08:52 AM posted to rec.photo.digital
Me
external usenet poster
 
Posts: 470
Default The base ("native") ISO of a sensor

On 28/05/2017 1:31 AM, Alfred Molon wrote:
In article , Me says...

On 27/05/2017 5:19 PM, Alfred Molon wrote:
In article , Me says...
Oh nice.
Bill Claff has produced an interactive chart showing comparison between
set ISO and measured ISO.
Olympus OMD E1 MkII overstates real ISO by 1.23 stops!
Something many fanboys won't want to accept I guess - those ISO3200
shots are actually only ISO 1365 - LOL.
He's also measured base/native ISO is ISO 200.
http://photonstophotos.net/Charts/Measured_ISO.htm

He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II.
But the exposure time at ISO 64 is three times longer than at ISO 200,
so clearly this Bill Claff is wrong.

DXO say the same, so no, Bill Claff is not wrong:
https://www.dxomark.com/Cameras/Comp..._1136_1070_909
Olympus lie about ISO. Big lies - Trump style lies.


No.

If the exposure time at ISO 64 is *three times* the exposure time at ISO
200, then both ISO settings do not have the same "true ISO" of 83.

That is a *fact* and if DXOMark or whoever say otherwise, they are
wrong.

Don't be silly.
Base ISO (set in camera) is 200 = real ISO 83. This answers your
original question about "native" or "base" ISO of the sensor.

If you don't want to believe that Olympus OMD EM1 real ISO is 1.23 stops
below stated ISO, bully for you.
I don't really care.
  #19  
Old May 28th 17, 08:55 AM posted to rec.photo.digital
Me
external usenet poster
 
Posts: 470
Default The base ("native") ISO of a sensor

On 28/05/2017 6:52 PM, RichA wrote:
On Saturday, 27 May 2017 04:44:29 UTC-4, Me wrote:
On 27/05/2017 5:19 PM, Alfred Molon wrote:
In article , Me says...
Oh nice.
Bill Claff has produced an interactive chart showing comparison between
set ISO and measured ISO.
Olympus OMD E1 MkII overstates real ISO by 1.23 stops!
Something many fanboys won't want to accept I guess - those ISO3200
shots are actually only ISO 1365 - LOL.
He's also measured base/native ISO is ISO 200.
http://photonstophotos.net/Charts/Measured_ISO.htm

He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II.
But the exposure time at ISO 64 is three times longer than at ISO 200,
so clearly this Bill Claff is wrong.

DXO say the same, so no, Bill Claff is not wrong:
https://www.dxomark.com/Cameras/Comp..._1136_1070_909
Olympus lie about ISO. Big lies - Trump style lies.


DXO is for zombies. They think camera lenses "change their physical shaprness characteristics" with sensor size and resolution. News flash, DXO, they don't.
If they had an interferometer, they'd SEE that.

"
What a load of crap. Give some example, instead of vague waffling, about
where and how DXO is wrong.


  #20  
Old May 28th 17, 08:55 AM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default The base ("native") ISO of a sensor

In article ,
RichA wrote:

On Saturday, 27 May 2017 04:44:29 UTC-4, Me wrote:
On 27/05/2017 5:19 PM, Alfred Molon wrote:
In article , Me says...
Oh nice.
Bill Claff has produced an interactive chart showing comparison between
set ISO and measured ISO.
Olympus OMD E1 MkII overstates real ISO by 1.23 stops!
Something many fanboys won't want to accept I guess - those ISO3200
shots are actually only ISO 1365 - LOL.
He's also measured base/native ISO is ISO 200.
http://photonstophotos.net/Charts/Measured_ISO.htm

He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II.
But the exposure time at ISO 64 is three times longer than at ISO 200,
so clearly this Bill Claff is wrong.

DXO say the same, so no, Bill Claff is not wrong:
https://www.dxomark.com/Cameras/Comp...M-D-E-M1-Mark-
II-versus-Olympus-PEN-F-versus-Olympus-OM-D-E-M1___1136_1070_909
Olympus lie about ISO. Big lies - Trump style lies.


DXO is for zombies. They think camera lenses "change their physical
shaprness characteristics" with sensor size and resolution. News flash, DXO,
they don't.
If they had an interferometer, they'd SEE that.


The DxO test cameras and lenses when making profiles for their reputable
soft. They share that very useful data.

You can think what you like about how they balance their "scores" but
the data in graphs and tables is very interesting.
--
teleportation kills
 




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