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Sensor noise: Nikon D200 versus Canon S70



 
 
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  #1  
Old September 18th 06, 06:17 AM posted to rec.photo.digital
Roger N. Clark (change username to rnclark)
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Posts: 1,818
Default Sensor noise: Nikon D200 versus Canon S70

I've completed two new digital camera analyses:

The Nikon D200 Digital Camera:
Sensor Noise, Dynamic Range, and Full Well Analysis
http://www.clarkvision.com/imagedeta...ion-nikon-d200

Compare those results to a small pixel P&S camera:

The Canon S70 Digital Camera:
Sensor Noise, Dynamic Range, and Full Well Analysis
http://www.clarkvision.com/imagedeta...tion-canon-s70

I've included comparisons of the above results in
some new figures (3b, 6 and 7) and discussion on this page:

Digital Cameras: Does Pixel Size Matter?
Factors in Choosing a Digital Camera
http://www.clarkvision.com/imagedeta...el.size.matter

Roger
  #2  
Old September 18th 06, 06:20 AM posted to rec.photo.digital
Paul Rubin
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Posts: 883
Default Sensor noise: Nikon D200 versus Canon S70

"Roger N. Clark (change username to rnclark)" writes:
I've completed two new digital camera analyses:
The Nikon D200 Digital Camera:...
The Canon S70 Digital Camera:...


Cool. Do you want similar data from other cameras?
  #3  
Old September 18th 06, 03:49 PM posted to rec.photo.digital
acl
external usenet poster
 
Posts: 1,389
Default Sensor noise: Nikon D200 versus Canon S70

Roger N. Clark (change username to rnclark) wrote:
I've completed two new digital camera analyses:

The Nikon D200 Digital Camera:
Sensor Noise, Dynamic Range, and Full Well Analysis
http://www.clarkvision.com/imagedeta...ion-nikon-d200

Compare those results to a small pixel P&S camera:

The Canon S70 Digital Camera:
Sensor Noise, Dynamic Range, and Full Well Analysis
http://www.clarkvision.com/imagedeta...tion-canon-s70

I've included comparisons of the above results in
some new figures (3b, 6 and 7) and discussion on this page:

Digital Cameras: Does Pixel Size Matter?
Factors in Choosing a Digital Camera
http://www.clarkvision.com/imagedeta...el.size.matter

Roger



Roger,
How do all the Canon cameras manage such low read noises? I did ask once
before, and you said you also found it strange that they managed to
reduce read noise to such low levels for their CMOS sensors. Well, it's
equally low for this compact, which has a CCD. Any idea how this can
happen (except by some very effective image processing before doing
anything else to the raw data)?

Cheers.
  #4  
Old September 19th 06, 01:05 AM posted to rec.photo.digital
Bart van der Wolf
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Posts: 314
Default Sensor noise: Nikon D200 versus Canon S70


"acl" wrote in message
...
SNIP
How do all the Canon cameras manage such low read noises?


http://web.canon.jp/Imaging/cmos/technology-e/noise_reduction.html

SNIP
Any idea how this can happen (except by some very effective image
processing before doing anything else to the raw data)?


There may be some specific noise suppression in the DIGIC processor as
well, but at least it is not obvious (apart from the absence of
noise).

--
Bart

  #5  
Old September 19th 06, 02:53 AM posted to rec.photo.digital
acl
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Posts: 1,389
Default Sensor noise: Nikon D200 versus Canon S70

Hello Bart,


Bart van der Wolf wrote:
"acl" wrote in message
...
SNIP
How do all the Canon cameras manage such low read noises?


http://web.canon.jp/Imaging/cmos/technology-e/noise_reduction.html


Right, but the S70 has a CCD, so it's not what is described there. The
S70 has extremely low read noise (as measured by Roger) for a CCD. It's
lower than most CCDs for scientific applications (I asked people at the
place where I work who deal with these things about usual read noise
levels, as I personally am clueless in practical matters).

SNIP
Any idea how this can happen (except by some very effective image
processing before doing anything else to the raw data)?


There may be some specific noise suppression in the DIGIC processor as
well, but at least it is not obvious (apart from the absence of
noise).


I didn't mean the same sort of thing that Neat Image (say) does. But I
always had trouble understanding how else they get the read noise so
low (I didn't have quantitative data, but looking at high ISO images in
the shadows it looked quite incredible). I think it is clear that some
very clever and effective processing is taking place.

At least, I can't think of any other explanation. But this is still
strange, how is it possible that Canon come up with such an algorithm
but nobody else?

  #6  
Old September 19th 06, 04:07 AM posted to rec.photo.digital
Roger N. Clark (change username to rnclark)
external usenet poster
 
Posts: 1,818
Default Sensor noise: Nikon D200 versus Canon S70

Paul Rubin wrote:

"Roger N. Clark (change username to rnclark)" writes:

I've completed two new digital camera analyses:
The Nikon D200 Digital Camera:...
The Canon S70 Digital Camera:...


Cool. Do you want similar data from other cameras?


Yes, I would. Others are doing these analyses too, and I've
collected the information and summarized it in Tables 1-4
he
http://www.clarkvision.com/imagedeta...ignal.to.noise

But most efforts are by amateur astronomers trying for
cameras more suited to low light work.
I would be interested in filling in more data
between the 2.3 and 6 micron pixel range, and if any camera
comes out much below 2.3 microns.

A requirement is that the camera must put out raw data.
Taking the data is pretty easy. Another requirement
is that there is software to get the linear raw data
from the raw file. Then it takes me several days
of work to analyze and write it up.

Roger
  #7  
Old September 19th 06, 04:22 AM posted to rec.photo.digital
Roger N. Clark (change username to rnclark)
external usenet poster
 
Posts: 1,818
Default Sensor noise: Nikon D200 versus Canon S70

acl wrote:

Hello Bart,

Bart van der Wolf wrote:

"acl" wrote in message
. be...
SNIP

How do all the Canon cameras manage such low read noises?


http://web.canon.jp/Imaging/cmos/technology-e/noise_reduction.html

Right, but the S70 has a CCD, so it's not what is described there. The
S70 has extremely low read noise (as measured by Roger) for a CCD. It's
lower than most CCDs for scientific applications (I asked people at the
place where I work who deal with these things about usual read noise
levels, as I personally am clueless in practical matters).


Canon's S60 camera has much worse read noise, so they
have certainly done something different on the S70. One trick
used in CCDs is to read the signal multiple times effectively
averaging the read noise toward zero. I don't know if
Canon does some trick like that (the web page
you reference does imply multiple reads).

Any idea how this can happen (except by some very effective image
processing before doing anything else to the raw data)?


There may be some specific noise suppression in the DIGIC processor as
well, but at least it is not obvious (apart from the absence of
noise).


I didn't mean the same sort of thing that Neat Image (say) does. But I
always had trouble understanding how else they get the read noise so
low (I didn't have quantitative data, but looking at high ISO images in
the shadows it looked quite incredible). I think it is clear that some
very clever and effective processing is taking place.

At least, I can't think of any other explanation. But this is still
strange, how is it possible that Canon come up with such an algorithm
but nobody else?


I don't think they are averaging pixels or doing post processing
on the raw data. That would show in the spatial resolution,
and it would be especially bad on stars. Nikon's median
filter shows such effects, for example.

Roger
  #8  
Old September 24th 06, 07:59 PM posted to rec.photo.digital
[email protected]
external usenet poster
 
Posts: 69
Default Sensor noise: Nikon D200 versus Canon S70

"Bart van der Wolf" writes:

"acl" wrote in message
...

....

Any idea how this can happen (except by some very effective image
processing before doing anything else to the raw data)?


There may be some specific noise suppression in the DIGIC processor
as well, but at least it is not obvious (apart from the absence of
noise).


Most of it is in the much inproved photo-diode resetting in CMOS
units, and using double correlation read-outs.

--
Paul Repacholi 1 Crescent Rd.,
+61 (08) 9257-1001 Kalamunda.
West Australia 6076
comp.os.vms,- The Older, Grumpier Slashdot
Raw, Cooked or Well-done, it's all half baked.
EPIC, The Architecture of the future, always has been, always will be.
 




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