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dpreview also tries to teach the trolls about ISO/aperture :)



 
 
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  #11  
Old September 10th 17, 08:41 AM posted to rec.photo.digital
android
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Posts: 3,854
Default dpreview also tries to teach the trolls about ISO/aperture :)

In article ,
Sandman wrote:

In article , PeterN wrote:

snip


Sandman:
Furthermore, EV+5 on one camera is NOT the same as EV+5 on another
camera, like ISO is trying to be.


Because adaptation of methods of exposure varies, ISO should not be
considered an absolute measurement of sensitivity, but merely a
reasonable guideline. That is one of the reasons a lot of us bracket
exposures.


But the point is, ISO *was* an absolute measurement of sensitivity, meaning
that one film of ISO400 and another film of ISO400 was equally sensitive to
light, that was the entire point of ISO.


Youpp! An gave us Ansel Adams zonesystem even though he used ASA, me
thinks...

Now, when digital rolled around, they adopted ISO to mean sensor
amplification, but the problem was that ISO is sensitivity over a unit area,
not over the exposed area (since that was pretty much the same back in 135
days), but digital cameras can't use a standard that is relevant to unit
areas when each camera had different amount of such unit areas


Which is rather useless compared to the above, but gives some sort of
reference for what middle grey should look like...
--
teleportation kills
  #12  
Old September 10th 17, 10:01 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default dpreview also tries to teach the trolls about ISO/aperture :)

On 10 Sep 2017 07:27:26 GMT, Sandman wrote:

In article , PeterN wrote:

snip


Sandman:
Furthermore, EV+5 on one camera is NOT the same as EV+5 on another
camera, like ISO is trying to be.


Because adaptation of methods of exposure varies, ISO should not be
considered an absolute measurement of sensitivity, but merely a
reasonable guideline. That is one of the reasons a lot of us bracket
exposures.


But the point is, ISO *was* an absolute measurement of sensitivity, meaning
that one film of ISO400 and another film of ISO400 was equally sensitive to
light, that was the entire point of ISO.

Now, when digital rolled around, they adopted ISO to mean sensor
amplification, but the problem was that ISO is sensitivity over a unit area,
not over the exposed area (since that was pretty much the same back in 135
days), but digital cameras can't use a standard that is relevant to unit
areas when each camera had different amount of such unit areas


They can, when what matters is not the total amount of light falling
on the entire sensor but the amount of light which falls on a unit
area of sensor.

Those pixels in the unit area don't care what is happening in the
neighbouring unit area. All that matters to them is the amount of
light which falls upon them.
--

Regards,

Eric Stevens
  #13  
Old September 10th 17, 10:03 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default dpreview also tries to teach the trolls about ISO/aperture :)

On 10 Sep 2017 07:23:32 GMT, Sandman wrote:

In article , Eric Stevens wrote:

Sandman:
https://www.dpreview.com/articles/2666934640/what-is-

equivalence-and-

why-should-i-care


It's funny, this article contains pretty much the exact same
key points and examples I showed the trolls here a couple of
years ago, where you need to adjust the aperture *AND* the ISO
to get similar end-result when it comes to sensor
amplification.

The example shows a MFT sensor having to adjust its aperture
by the crop factor and the ISO by the crop factor squared to
receive the same amount of total light as the FF sensor to
produce an image with the same light intensity and the same
sensor amplification.

Now, where have I heard this before? :-D

Sandman How to measure ISO 11/28/2015


"FF: 1/250, f5.6, ISO 800
MFT: 1/250, f2.8, ISO 200

The above is the same *amount of light* on the sensor, which
creates as identical image as possible using different sensor
technologies. Also, you adjust the ISO by the crop factor
squared to match the signal amplification of the larger
sensor, so you will get very equivalent noise."

In the dpreview article they used the exact same ratios:

FF: f5.6 ISO 3200
MFT: f2.8 ISO 800

And the end result was similarly amplified images. Go figure


Eric Stevens:
Go figure indeed. If only the man applied the mathematics of the
situation from beginning to end he would not have reached the
(erroneous) conclusion he has.

Sandman:
Take it up with dpreview, same math, same examples, same
conclusions. Go figure


Same logical errors.


Same hot air from the trolls of rpd


I could explain it but it requires diagrams which I can't put on rpd
and it requires algebra which is too complicated to be published in a
text news group. One day I might produce it as a PDF, but it's quite a
lot of work.
--

Regards,

Eric Stevens
  #14  
Old September 10th 17, 10:43 AM posted to rec.photo.digital
Sandman
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Posts: 5,467
Default dpreview also tries to teach the trolls about ISO/aperture :)

In article , Eric Stevens wrote:

PeterN:
Because adaptation of methods of exposure varies, ISO should not
be considered an absolute measurement of sensitivity, but merely
a reasonable guideline. That is one of the reasons a lot of us
bracket exposures.


Sandman:
But the point is, ISO *was* an absolute measurement of
sensitivity, meaning that one film of ISO400 and another film of
ISO400 was equally sensitive to light, that was the entire point
of ISO.


Now, when digital rolled around, they adopted ISO to mean sensor
amplification, but the problem was that ISO is sensitivity over a
unit area, not over the exposed area (since that was pretty much
the same back in 135 days), but digital cameras can't use a
standard that is relevant to unit areas when each camera had
different amount of such unit areas


They can, when what matters is not the total amount of light falling
on the entire sensor but the amount of light which falls on a unit
area of sensor.


Incorrect on several accounts. First, the amount of light that falls on a
unit area is never "the matter" to the photographer. The end result is.

Secondly, when you have different amount of unit areas in play, whatever
"iso" one unit area may or may not be in relation to is irrelevant.

Thirdly, ISO for digital cameras does NOT means X amount of light gathered
per unit area, that's the *film* usage of ISO. "ISO" for digital cameras is
an arbitrary value to match the *lightness* of the film-equivalent of that
ISO setting.

So when you talk about "ISO" in digital cameras, it has absolutely nothing to
do with light per unit area other than the camera trying to emulate the
result of a ISO analog film. Which, depending on your sensors size means you
have to amplify it more or less than another camera.

Those pixels in the unit area don't care what is happening in the
neighbouring unit area. All that matters to them is the amount of
light which falls upon them.


They are also not more "sensitive" depending on your ISO settings. They are
fixed. With less total light, the signal needs to be amplified more to match
the brightness of the film ISO emulation step.



--
Sandman
  #15  
Old September 10th 17, 10:45 AM posted to rec.photo.digital
Sandman
external usenet poster
 
Posts: 5,467
Default dpreview also tries to teach the trolls about ISO/aperture :)

In article , Eric Stevens wrote:

Eric Stevens:
Same logical errors.


Sandman:
Same hot air from the trolls of rpd


I could explain it but it requires diagrams which I can't put on rpd
and it requires algebra which is too complicated to be published in
a text news group. One day I might produce it as a PDF, but it's
quite a lot of work.


Like I said - more hot air from the trolls. :-D

And it's also ironic that Eric, in a photography usenet group, seem to want
to claim there is no way to convey something other than text here :-D

--
Sandman
  #16  
Old September 10th 17, 10:50 AM posted to rec.photo.digital
Sandman
external usenet poster
 
Posts: 5,467
Default dpreview also tries to teach the trolls about ISO/aperture :)

In article .com,
Savageduck wrote:

Sandman:
ISO is irrelevant. Camera makers should just have a setting for
amplification. So you set the camera to EV+X to have the signal
amplified x amount of times. And high-end cameras can have it
pushed to EV+8 or EV+10 while more normal cameras maxes out at
EV+6 or something.


Furthermore, EV+5 on one camera is NOT the same as EV+5 on
another camera, like ISO is trying to be.


RichA:
That's actually not a bad idea. Problem is, camera makers are
still pandering to old film shooters, hence ISO which is the ASA
of digital. Same reason perhaps we still have F-stops and not
T-stops for still shooting, though that's probably as much about
marketing as functionality.


One of the interesting features with my X-T2 is the EV adjustment
dial option. It has the typical +3/-3 EV dial settings. However, it
also has a “C” setting which passes control to the front control
wheel and extends the EV adjustment to +5/-5 EV. and acts very much
like an amplification gain adjustment to the base sensor generated
signal.


Are you sure? Can't say anything about that particular camera, but usually
the EV setting is for auto-compensating the *exposure*, not the sensor
amplification. I.e. if you have the camera set in aperture-priority mode and
it decides on 1/250 for f5.6, then moving the EV to EV+1 would just set it to
expose at 1/125 f5.6 for instance, i.e. the "ISO" setting, or rather the
sensor amplification remains the same.

Is the -5/+5 setting different in your camera, or is the entire EV function
different?

--
Sandman
  #17  
Old September 10th 17, 10:51 AM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default dpreview also tries to teach the trolls about ISO/aperture :)

In article ,
Sandman wrote:
[---]
Like I said - more hot air from the trolls. :-D


Nice autumn day today: A tad chilly but the sky is clear and it ain't
that windy... Are you going hot air ballooning today? You do seem to
have all the toys! :-))

http://www.dmi.dk/uploads/tx_dmidata.../1/c/59b50265c
1486.png
--
teleportation kills
  #18  
Old September 10th 17, 03:01 PM posted to rec.photo.digital
Savageduck[_3_]
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Posts: 16,487
Default dpreview also tries to teach the trolls about ISO/aperture :)

On 2017-09-10 09:50:58 +0000, Sandman said:

In article .com,
Savageduck wrote:

Sandman:
ISO is irrelevant. Camera makers should just have a setting for
amplification. So you set the camera to EV+X to have the signal
amplified x amount of times. And high-end cameras can have it
pushed to EV+8 or EV+10 while more normal cameras maxes out at
EV+6 or something.

Furthermore, EV+5 on one camera is NOT the same as EV+5 on
another camera, like ISO is trying to be.

RichA:
That's actually not a bad idea. Problem is, camera makers are
still pandering to old film shooters, hence ISO which is the ASA
of digital. Same reason perhaps we still have F-stops and not
T-stops for still shooting, though that's probably as much about
marketing as functionality.


One of the interesting features with my X-T2 is the EV adjustment
dial option. It has the typical +3/-3 EV dial settings. However, it
also has a “C” setting which passes control to the front control
wheel and extends the EV adjustment to +5/-5 EV. and acts very much
like an amplification gain adjustment to the base sensor generated
signal.


Are you sure?


No I am not sure. I am just relaying what seems to be happening.

Can't say anything about that particular camera, but usually
the EV setting is for auto-compensating the *exposure*, not the sensor
amplification.


That is my expectation of normal function. However, when in manual, or
shutter priority, I see changes made to EV comp in reaction to speed
adjustments.

I.e. if you have the camera set in aperture-priority mode and
it decides on 1/250 for f5.6, then moving the EV to EV+1 would just set it to
expose at 1/125 f5.6 for instance, i.e. the "ISO" setting, or rather the
sensor amplification remains the same.


....and that is what I experience when using Aperture priority.

Is the -5/+5 setting different in your camera, or is the entire EV function
different?


All I can tell you is how using the Custom, "C" setting on the EV dial
expands the EV range from +3/-3 to +5/-5, and moves control to the
front control wheel, and how making various exposure adjustments in
different exposure modes effects what I see to change with the EV comp
settings.
https://www.dropbox.com/s/g2pph9alnfwz3ot/screenshot_168.png

In Aperture priority mode that EV compensation acts as you would
expect, but with the expanded compensation range (+5/-5) controlled via
the front control wheel rather than the EV dial.

In Shutter priority the behavior is different. Using the EV
compensation in the normal +3/-3 operation I see only the expected, and
normal EV indicator/scale on the LCD/EVF regardless of speed setting.
However, if the Custom “C” EV is selected, when speed is adjusted the
EV can be seen to move without touching the EV adjustment.
https://www.dropbox.com/s/lf4szsegb14pldk/screenshot_169.png

In full Manual mode the same movement of the EV compensation
indicator/scale in the LCD/EVF is shown regardless of using normal or
“C” for EV comp.

It just seems a bit odd to me when compared with what I had been used
to with my Nikon DSLRs. It might just be a Fujifilm mirrorless thing.
;-)

--
Regards,

Savageduck

  #19  
Old September 10th 17, 05:49 PM posted to rec.photo.digital
Sandman
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Posts: 5,467
Default dpreview also tries to teach the trolls about ISO/aperture :)

In article 2017091007015440977-savageduck1@REMOVESPAMmecom, Savageduck
wrote:

Sandman:
Is the -5/+5 setting different in your camera, or is the entire EV
function different?


All I can tell you is how using the Custom, "C" setting on the EV
dial expands the EV range from +3/-3 to +5/-5, and moves control to
the front control wheel, and how making various exposure adjustments
in different exposure modes effects what I see to change with the EV
comp settings.
https://www.dropbox.com/s/g2pph9alnfwz3ot/screenshot_168.png


Yeah, that seems to suggest that it is used to set aperture and shutter
(exposure) compensation, not sensor amplification. And the extended range is
probably due to the front dial is stepless while the EV dial has printed
steps.

It just seems a bit odd to me when compared with what I had been
used to with my Nikon DSLRs. It might just be a Fujifilm mirrorless
thing. ;-)


Yeah, few Nikon DSLR's have a EV dial to begin with, most have a EV button
and then you use the command dial to set it. I think my D800 has a range of
+/- 4 steps if I remember correctly.

Both my Nikon Df and my Sony A7 have a EV dial that goes from -3 to +3

--
Sandman
  #20  
Old September 10th 17, 06:24 PM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default dpreview also tries to teach the trolls about ISO/aperture :)

In article ,
Sandman wrote:

In article 2017091007015440977-savageduck1@REMOVESPAMmecom, Savageduck
wrote:

Sandman:
Is the -5/+5 setting different in your camera, or is the entire EV
function different?


All I can tell you is how using the Custom, "C" setting on the EV
dial expands the EV range from +3/-3 to +5/-5, and moves control to
the front control wheel, and how making various exposure adjustments
in different exposure modes effects what I see to change with the EV
comp settings.
https://www.dropbox.com/s/g2pph9alnfwz3ot/screenshot_168.png


Yeah, that seems to suggest that it is used to set aperture and shutter
(exposure) compensation, not sensor amplification. And the extended range is
probably due to the front dial is stepless while the EV dial has printed
steps.

It just seems a bit odd to me when compared with what I had been
used to with my Nikon DSLRs. It might just be a Fujifilm mirrorless
thing. ;-)


Yeah, few Nikon DSLR's have a EV dial to begin with, most have a EV button
and then you use the command dial to set it. I think my D800 has a range of
+/- 4 steps if I remember correctly.

Both my Nikon Df and my Sony A7 have a EV dial that goes from -3 to +3


Do you intend to get the Sony AIII by Christmas?
--
teleportation kills
 




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