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Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)



 
 
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  #21  
Old October 16th 09, 08:10 AM posted to rec.photo.digital.slr-systems
David J Taylor[_11_]
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Posts: 451
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)


"Paul Furman" wrote in message
...
Alan Browne wrote:
Paul Furman wrote:
DRS wrote:

Why do Nikons seem to have a base ISO of 200? Is it a trade off of
some kind?

It allows a higher max ISO.


No relevance really.


Is it just coincidence that low-ISO sensors on P&S start at lower ISOs?
I don't understand the details but the general principal seems to apply.


It could be that the P&S small-pixel sensors are relatively less efficient
in light capture (the non-sensitive electronics occupies a larger fraction
of the pixel area), and hence need more light to fill the well. This
being an additional problem to their small size, and hence fewer photos,
and hence greater shot-noise.

David

  #22  
Old October 16th 09, 03:21 PM posted to rec.photo.digital.slr-systems,alt.photography
Peter[_7_]
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Posts: 2,078
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)

"D. Peter Maus" wrote in message
...
On 10/14/09 16:37 , Savageduck wrote:
On 2009-10-14 14:07:08 -0700, "D. Peter Maus"
said:

On 10/14/09 15:53 , Savageduck wrote:
On 2009-10-14 11:04:56 -0700, "D. Peter Maus"
said:

On 10/14/09 12:56 , Savageduck wrote:
On 2009-10-14 10:45:43 -0700, Alan Browne
said:

Read all the gory details of this new body:

http://www.dpreview.com/news/0910/09101402nikonD3s.asp

Interesting.
It seems to me the real benefit is going to be in high ISO
performance
and the addition of sensor cleaning. I am not drawn to the video in
DSLR
trend.
Not being a pro or independantly wealthy I guess I am going to stick
with my D300 for now.



That D300 is no slouch, either.

I'm happy with it, and I still have my D70 lifeboat.


LOL! Yeah, I still shoot my D70 daily. If you like D300 see if you can
get your hands on a D700 for a weekend.


The D700 thing is something I have been thinking of for a while now.

You'll never need another woman.


Well I have been on my own for almost two years now, and even though I
have the social life of a stump, a little feminine companionship
wouldn't be too bad from time to time.

There is nothing more disturbing than a 60 year old in hormonal
distress. :-)



I'm right behind you at 58.



At 72 I'm ahead of both. Lots of fun years left, hopefully for all of us.

Differences:
Although I have a D300, with my 200 as a backup, I am seriously thinking of
a D5000 because the articulated LCD should give my back more mileage.


--
Peter

  #23  
Old October 16th 09, 03:26 PM posted to rec.photo.digital.slr-systems,alt.photography
Peter[_7_]
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Posts: 2,078
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)

"John Sheehy" wrote in message
...
"DRS" wrote in
. au:

Why do Nikons seem to have a base ISO of 200? Is it a trade off of some
kind?


The D3 uses a low silicon fill factor, and makes up for it with large
microlenses, which, of course, fill the wells faster. In order to meter
at
ISO 100, the camera would have very little RAW highlight headroom, so ISOs
under 200 are only offered as special modes. Apparently, they use the low
fill factor to get more noiseless electronics at the photosites. This
keeps read noise down a bit, but increases shot noise a little, too.



Would you please explain this concept in English? I know about SNR and why I
get more noise at a higher ISO, but I don't understand the difference
between read noise and shot noise.

--
Peter

  #24  
Old October 16th 09, 04:00 PM posted to rec.photo.digital.slr-systems,alt.photography
Floyd L. Davidson
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Posts: 5,138
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)

"Peter" wrote:
"John Sheehy" wrote in message
...
"DRS" wrote in
. au:

Why do Nikons seem to have a base ISO of 200? Is it a trade off of some
kind?


The D3 uses a low silicon fill factor, and makes up for it with large
microlenses, which, of course, fill the wells faster.
In order to meter at
ISO 100, the camera would have very little RAW highlight headroom, so ISOs
under 200 are only offered as special modes. Apparently, they use the low
fill factor to get more noiseless electronics at the photosites. This
keeps read noise down a bit, but increases shot noise a little, too.



Would you please explain this concept in English? I know about SNR and why I
get more noise at a higher ISO, but I don't understand the difference
between read noise and shot noise.


"Photon shot noise", or "photon noise", or "Poisson
noise" or "shot noise" are all references to the fact
that light doesn't hit the sensor at a constant steady
rate. The rate variation results in noise because the
actual exposure is for some specified interval. Two
adjacent pixel locations may be illuminated exactly the
same, but in the particular interval that light was
allowed to fall on them it is very likely that one pixel
will get more light (light for that pixel was arriving
at a faster rate than for the other). The difference
between the signal from those two pixels is shot noise.

Shot noise looks like a paper covered with a mix of salt
and pepper! It is also greater for more exposure (the
variation in rate increases as the amount of light
increases). Hence the place it is usually seen in
images is in the sky, or clouds, or other featureless
highlights. (So maybe we should say it looks like a
paper covered with a mixture of white salt and light
grey pepper.)

Above a certain amount of exposure, the SNR of an image
is very likely to be determined by photon noise, in
which case it is called "photon noise limited".

Read noise is all noise that is in the image as a result
of reading the data from the sensor (even if the lens
cap is on and absolutely no light has hit the sensor and
therefore the signal is 0). The base level of analog
voltage fluctuation on the sensor adds to it. Things
such as clock frequency variations in the ADC add to it.
In most discussions quantization distortion is included
in the "read noise".

Read noise has, like shot noise, a Gaussian distribution
so it is essentially random, and will mostly be seen in
the shadows. To continue the analogy used above, it
looks very much like a paper covered with mixture of
black pepper and grey pepper.

Below a certain amount of exposure, the SNR of an image
is very likely to be determined by read noise instead of
shot noise. (Generally that is not a good thing.)
Because read noise will be seen in the shadows it is
generally more annoying to the human eye.

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)
  #25  
Old October 16th 09, 04:55 PM posted to rec.photo.digital.slr-systems,alt.photography
Peter[_7_]
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Posts: 2,078
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)

"Floyd L. Davidson" wrote in message
...
"Peter" wrote:
"John Sheehy" wrote in message
...
"DRS" wrote in
. au:

Why do Nikons seem to have a base ISO of 200? Is it a trade off of
some
kind?

The D3 uses a low silicon fill factor, and makes up for it with large
microlenses, which, of course, fill the wells faster.
In order to meter at
ISO 100, the camera would have very little RAW highlight headroom, so
ISOs
under 200 are only offered as special modes. Apparently, they use the
low
fill factor to get more noiseless electronics at the photosites. This
keeps read noise down a bit, but increases shot noise a little, too.



Would you please explain this concept in English? I know about SNR and why
I
get more noise at a higher ISO, but I don't understand the difference
between read noise and shot noise.


"Photon shot noise", or "photon noise", or "Poisson
noise" or "shot noise" are all references to the fact
that light doesn't hit the sensor at a constant steady
rate. The rate variation results in noise because the
actual exposure is for some specified interval. Two
adjacent pixel locations may be illuminated exactly the
same, but in the particular interval that light was
allowed to fall on them it is very likely that one pixel
will get more light (light for that pixel was arriving
at a faster rate than for the other). The difference
between the signal from those two pixels is shot noise.

Shot noise looks like a paper covered with a mix of salt
and pepper! It is also greater for more exposure (the
variation in rate increases as the amount of light
increases). Hence the place it is usually seen in
images is in the sky, or clouds, or other featureless
highlights. (So maybe we should say it looks like a
paper covered with a mixture of white salt and light
grey pepper.)

Above a certain amount of exposure, the SNR of an image
is very likely to be determined by photon noise, in
which case it is called "photon noise limited".

Read noise is all noise that is in the image as a result
of reading the data from the sensor (even if the lens
cap is on and absolutely no light has hit the sensor and
therefore the signal is 0). The base level of analog
voltage fluctuation on the sensor adds to it. Things
such as clock frequency variations in the ADC add to it.
In most discussions quantization distortion is included
in the "read noise".

Read noise has, like shot noise, a Gaussian distribution
so it is essentially random, and will mostly be seen in
the shadows. To continue the analogy used above, it
looks very much like a paper covered with mixture of
black pepper and grey pepper.

Below a certain amount of exposure, the SNR of an image
is very likely to be determined by read noise instead of
shot noise. (Generally that is not a good thing.)
Because read noise will be seen in the shadows it is
generally more annoying to the human eye.

Thanks for that explanation. My interest as a photo artist is simply to make
a nice picture. When Nikon says I can shoot at a higher ISO with less noise,
I am skeptical. I have a friend who claims he shoot a D300 at ISO 1,600
without little perceptible noise. Yet I have not found that to be the case
on my D300.



--
Peter

  #26  
Old October 16th 09, 05:09 PM posted to rec.photo.digital.slr-systems
David J Taylor[_11_]
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Posts: 451
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)


"Peter" wrote in message
...
[]
Would you please explain this concept in English? I know about SNR and
why I get more noise at a higher ISO, but I don't understand the
difference between read noise and shot noise.


See:

http://www.clarkvision.com/imagedeta...mance.summary/

and related pages.

David

  #27  
Old October 16th 09, 05:15 PM posted to rec.photo.digital.slr-systems
David J Taylor[_11_]
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Posts: 451
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)


"Peter" wrote in message
...
[]
Thanks for that explanation. My interest as a photo artist is simply to
make a nice picture. When Nikon says I can shoot at a higher ISO with
less noise, I am skeptical. I have a friend who claims he shoot a D300
at ISO 1,600 without little perceptible noise. Yet I have not found that
to be the case on my D300.


If you look closely enough, you will see noise even in ISO 100 images. My
Nikon D5000 has an ISO 3200 setting which produces better results than my
compact camera does at ISO 400. Is it noise-free? No. Is it usable for
the circumstances where I have to use ISO 3200? Most certainly.

If you want to "make a nice picture", ensure you have enough light that
you can shoot at ISO 100 with a small camera, ISO 200-400-800 with your
DSLR, according to what /you/ judge to be noise-free results, at the image
size you will finally be viewing.

Cheers,
David

  #28  
Old October 16th 09, 06:19 PM posted to rec.photo.digital.slr-systems
Gavin Jace
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Posts: 1
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)

On Fri, 16 Oct 2009 16:09:45 GMT, "David J Taylor"
wrote:


"Peter" wrote in message
...
[]
Would you please explain this concept in English? I know about SNR and
why I get more noise at a higher ISO, but I don't understand the
difference between read noise and shot noise.


See:

http://www.spamlinksnipped.com/image...mance.summary/

and related pages.

David


Except that that is nothing but blatant misinformation. He posts those
findings to slant them toward his own cameras, trying to justify his own
purchases. He never takes into account any newer technology that destroys
the results of all his old biases. Then idiots like you regurgitate those
pages to perpetuate his nonsense because you know no better.

  #29  
Old October 16th 09, 10:26 PM posted to rec.photo.digital.slr-systems,alt.photography
Alan Browne
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Posts: 12,640
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)

Paul Furman wrote:
Alan Browne wrote:
Paul Furman wrote:
DRS wrote:

Why do Nikons seem to have a base ISO of 200? Is it a trade off of
some kind?

It allows a higher max ISO.


No relevance really.


Is it just coincidence that low-ISO sensors on P&S start at lower ISOs?
I don't understand the details but the general principal seems to apply.


The lowest ISO should have no bearing on the max ISO.

With most sensors, gain (higher ISO numbers) is simply analog gain
(pre-conversion) for the first few stops (from say 100 - 800 or 1600)
and afterwards it is is digital gain. (Although recent higher ISO
cameras from Canon and Nikon may have more analog gain before relying on
digital). So there is no limit imposed by the lowest sensitivity.
  #30  
Old October 17th 09, 06:21 AM posted to rec.photo.digital.slr-systems,alt.photography
Dimitris M
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Posts: 119
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)

D300 can produce very acceptable photos even at ISO 3200 when and if the
light is almost daylight as color temp (over 4000 K) with a even smooth
spectrum. For ex the interior of a house illuminated from windows, when the
reflective surfaces are mostly neutral. No matter how low is this light. As
long as the light is of "full spectrum" even very dim, the picture will have
not suffer to much from noise. A second parameter is the dynamic range of
the light in the photo. If the darkest area in the photo is not darker than
5-7 EV, then this is a factor to not develop the noise in an inconvenient
way. So, even luminance and good spectrum are the factors that can produce
pictures with less ugly noise. The remaining noise is more even luminance
noise (less or no ugly chrominance), more like a powder, as film grain, that
sometimes can add to beautiful bokeh, if exists.



From the other hand a bad light source, as the green or orange mercury
street lights with the terrible spectrum, or the dim tungsten lights with
yellow or brown lampshade that produce light of very low temp, often less
than 2000K can push the cameras WB adjustment out of the limits even at ISO
200.



For ex if the light has a temp of 1800K (not rare), the blue channel is
almost absent. In that case if we (or the camera) try to correct the color,
not 100%, but even a little just to look more natural and full, we will
amplify the blue channel even by more than 5 EV,. That means that even if we
shot at 200 ISO, the blue channel will be amplified to even higher than ISO
6400 and then the noise will be terrible.



So under circumstances, we can have almost perfect photos at ISO 3200 and
under other very noisy under ISO 800 (or less). Bad light quality and wide
luminance range of the subject are the enemies of the low noise photo

--
Dimitris M



....I have a friend who claims he shoot a D300 at ISO 1,600 without little
perceptible noise. Yet I have not found that to be the case on my D300.



 




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