Very nice that you can do all this testing but it seems to me that your
basic testing is flawed because it is not possible to compare from one
camera to another because the shots are so different and so differently lit
and very different scenes.
"Pete D" <no@email.com> a écrit dans le message de news:
4621cbf5$0$25498$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
> Very nice that you can do all this testing but it seems to me that your
> basic testing is flawed because it is not possible to compare from one
> camera to another because the shots are so different and so differently
> lit and very different scenes.
>
When you read even for a few seconds, you'll discover that it is the same
subject, same framing, same camera, same light, the only changing parameter
is ISO.
From the noise point of view, this Pentax K10D is not better than the good
old Canon Rebel.
"Saguenay" <notyourbusiness@lapeste.com> wrote in message
news:4wpUh.9$iq5.5202@wagner.videotron.net...
>
> "Pete D" <no@email.com> a écrit dans le message de news:
> 4621cbf5$0$25498$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
>> Very nice that you can do all this testing but it seems to me that your
>> basic testing is flawed because it is not possible to compare from one
>> camera to another because the shots are so different and so differently
>> lit and very different scenes.
>>
>
> When you read even for a few seconds, you'll discover that it is the same
> subject, same framing, same camera, same light, the only changing
> parameter is ISO.
> From the noise point of view, this Pentax K10D is not better than the good
> old Canon Rebel.
>
> Mike
Mike,
Different cameras were taken from different places under different lighting
conditions how can you say they are the same? For a comparison to be able to
be made that actually means anything all cameras would need to be tested
under the same conditions where as many variables as possible were
eliminated and that would include trying to use the exact same lenses. I
would expect the XTi to be better but he used a known very sharp lens to do
the tests on the XTi and a known average performer on the K10D, also the
shots for the XTi were very close shots where the K10D and D200 for example
were long range shots, how do you conclude that they were the same??
I think you are missing the point a bit, these are explicitly image
noise tests, not lens tests, or sensor resolution tests. I do believe
you can make reasonable judgments about image noise from tests like
these in the real world.
My lens tests, which I have not started publishing yet, are shot under
controlled conditions, but still practical ones.
However, given what you have said, I might start including in my noise
tests an indoor shot under controlled lighting conditions.
For sensor noise tests it is not necessary to use the same lens, nor is
this even possible across a wide range of lens mounts, not to mention
that different cameras would need different lens focal lengths to give
the equivalent subject magnification on sensor.
My philosophy with all camera testing since I started doing so over 10
years ago has been practical testing in the real world. There are other
sources that do the lab testing in conditions no one will ever
experience, my choice was to provide an alternative that most shooters
could relate to. If you want the detailed numbers there are other sources.
Pete D wrote:
> "Saguenay" <notyourbusiness@lapeste.com> wrote in message
> news:4wpUh.9$iq5.5202@wagner.videotron.net...
>> "Pete D" <no@email.com> a écrit dans le message de news:
>> 4621cbf5$0$25498$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
>>> Very nice that you can do all this testing but it seems to me that your
>>> basic testing is flawed because it is not possible to compare from one
>>> camera to another because the shots are so different and so differently
>>> lit and very different scenes.
>>>
>> When you read even for a few seconds, you'll discover that it is the same
>> subject, same framing, same camera, same light, the only changing
>> parameter is ISO.
>> From the noise point of view, this Pentax K10D is not better than the good
>> old Canon Rebel.
>>
>> Mike
>
> Mike,
>
> Different cameras were taken from different places under different lighting
> conditions how can you say they are the same? For a comparison to be able to
> be made that actually means anything all cameras would need to be tested
> under the same conditions where as many variables as possible were
> eliminated and that would include trying to use the exact same lenses. I
> would expect the XTi to be better but he used a known very sharp lens to do
> the tests on the XTi and a known average performer on the K10D, also the
> shots for the XTi were very close shots where the K10D and D200 for example
> were long range shots, how do you conclude that they were the same??
>
>
>
"Wayne J. Cosshall" <wayne@dimagemaker.com> wrote in message
news:46229595$0$27883$afc38c87@news.optusnet.com.a u...
> Hi Pete,
>
> I think you are missing the point a bit, these are explicitly image noise
> tests, not lens tests, or sensor resolution tests. I do believe you can
> make reasonable judgments about image noise from tests like these in the
> real world.
>
> My lens tests, which I have not started publishing yet, are shot under
> controlled conditions, but still practical ones.
>
> However, given what you have said, I might start including in my noise
> tests an indoor shot under controlled lighting conditions.
>
If you are going to engage yourself in reinventing the wheel, you first have
to define a circle or it won't roll. What you are doing with your "reviews"
is a demonstration of the evolution of your intentions. They are still in
flux and need to be refined in order to avoid early ridicule from your
peers.
Everyone else uses a standard scene when demonstrating features of a
particular piece of camera gear. You should devise one too. If you did this,
your writings would have more credibility and your overall plan would evolve
the way you intend it to.
If you don't produce clearly measurable results from standardised
proceedures, you are in danger of not just missing the point but becoming
the target of some of Usenet's less polite netizens. This would start you on
a path you really don't want to take.
So Wayne. I believe you have the dedication to get your act together and the
contacts to make it work. Don't blow the opportunity by publishing "tests"
with no valid comparrisons or measurable examples.
--
"A picture might speak a thousand words
but what good is this to a person who will not listen"?
"Pete D" <no@email.com> wrote in
news:4621cbf5$0$25498$5a62ac22@per-qv1-newsreader-01.iinet.net.au:
> Very nice that you can do all this testing but it seems to me that
> your basic testing is flawed because it is not possible to compare
> from one camera to another because the shots are so different and so
> differently lit and very different scenes.
I'm not saying that it's Wayne's responsibility to do so, but it would be
nice to have a repository of RAW files from different cameras, of
"subjects" more suitable for examining camera performance:
1) Black frames of various exposure lengths.
3) Out-of focus color checkers amd/or Stouffer transparencies, properly
exposed (perhaps with a standard for the same exposure on various
cameras (ideally with the same t-mount manual-aparture lens, for
consistency of real-world exposure, but that would require one person
to do all of them), and clipped (all three RAW color channels clipped
in the brightest patch), and extremely under-exposed, as well.
4) Resolution tests.
.... all at all ISOs.
Real images are not very useful, IMO, for comparing cameras, as there are
too many variables involved. Detail in images makes noise measurement
impossible.
--
<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
"Saguenay" <notyourbusiness@lapeste.com> wrote in
news:4wpUh.9$iq5.5202@wagner.videotron.net:
> When you read even for a few seconds, you'll discover that it is the
> same subject, same framing, same camera, same light, the only changing
> parameter is ISO.
> From the noise point of view, this Pentax K10D is not better than the
> good old Canon Rebel.
It is still very subjective, though, and there are *NO* dark areas in the
images.
From what I gather from people who have tested the K10D more objectively,
it is the #1 DSLR for dynamic range at ISO 100, at the pixel level. The
1DSmkII might be close at the image level (dividing noise by the linear,
one-dimensional pixel resolution).
It has no real optimization at higher ISOs, though, like Canons do. Most
cameras don't; they have a single at-photosite read noise, and multiply
it in amplification, and then add the analog noise of the ADC, so the
total read noise as measured in electrons only improves ever so slightly
at higher ISOs, as opposed to dramatically with Canons. For most of
these cameras, the only benefit of higher ISOs is the brightness of the
review image; under-exposing at a lower ISO may provide almost the same
quality, without sacrificing highlight headroom. Quantization is not a
significant issue with these analog noise levels.
The standard deviation of an ISO 100 blackframe from the K10D (according
to my source) is about 0.9 DN/ADU. The Fuji SLRs, the Canon 1D* cameras,
start at about 1.3. Non-1D Canons are at 1.65 to 2.1, and most Nikons
are at about 3.0 or so. Some cameras clip the RAW data at black, and
some don't. These values are normalized to those that don't, as the
noise is only clipped near black in the cameras that do clip at black,
and not at higher luminance levels in any camera (blackframe noise must
be multiplied by about 1.64 for black-clipped RAW images).
With the K10D black noise at only 0.9 DN/ADU there is probably a little
bit of quantization noise, so ISO 200 probably is a bit better than ISO
100 under-exposed (ignoring the stop of highlights), so it has more value
than just a brigher review image or default conversion or JPEG.
The probably reason that the extra DR is not noticed in many DR reviews
is that the images are rendered with normal transfer curves, leaving the
extra shadow ranges down in the dark, where you can't distinguish them.
You really need to boost the shadows to appreciate the difference. There
is also the issue of where the camera exposes the middle grey in the RAW
data; this can vary quite a bit from camera to camera, and converters are
not consistent in the way they utilize RAW highlights.
--
<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
"Wayne J. Cosshall" <wayne@dimagemaker.com> wrote in message
news:46229595$0$27883$afc38c87@news.optusnet.com.a u...
> Hi Pete,
>
> I think you are missing the point a bit, these are explicitly image noise
> tests, not lens tests, or sensor resolution tests. I do believe you can
> make reasonable judgments about image noise from tests like these in the
> real world.
If you believe that different lenses will have no affect on apparent noise
then my time here is wasted and I will move on.
>
> My lens tests, which I have not started publishing yet, are shot under
> controlled conditions, but still practical ones.
As all comaprative testing must be to be comparative.
> However, given what you have said, I might start including in my noise
> tests an indoor shot under controlled lighting conditions.
Excellent.
> For sensor noise tests it is not necessary to use the same lens, nor is
> this even possible across a wide range of lens mounts, not to mention that
> different cameras would need different lens focal lengths to give the
> equivalent subject magnification on sensor.
Actually I think it would be fairly simple and easy to get a lot closer than
the comparison where you have used an ultra sharp macro lens and compared it
to a average kit lens under quite different lighting conditions.
> My philosophy with all camera testing since I started doing so over 10
> years ago has been practical testing in the real world.
At least try to make them similar, please.
> There are other sources that do the lab testing in conditions no one will
> ever experience, my choice was to provide an alternative that most
> shooters could relate to. If you want the detailed numbers there are other
> sources.
>
> Cheers,
>
> Wayne
>
> Wayne J. Cosshall
> Publisher, The Digital ImageMaker, http://www.dimagemaker.com/
> Blog http://www.digitalimagemakerworld.com/
> Publisher, Experimental Digital Photography
> http://www.experimentaldigitalphotography.com
> Personal art site http://www.cosshall.com/
>
>
>
> Pete D wrote:
>> "Saguenay" <notyourbusiness@lapeste.com> wrote in message
>> news:4wpUh.9$iq5.5202@wagner.videotron.net...
>>> "Pete D" <no@email.com> a écrit dans le message de news:
>>> 4621cbf5$0$25498$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
>>>> Very nice that you can do all this testing but it seems to me that your
>>>> basic testing is flawed because it is not possible to compare from one
>>>> camera to another because the shots are so different and so differently
>>>> lit and very different scenes.
>>>>
>>> When you read even for a few seconds, you'll discover that it is the
>>> same subject, same framing, same camera, same light, the only changing
>>> parameter is ISO.
>>> From the noise point of view, this Pentax K10D is not better than the
>>> good old Canon Rebel.
>>>
>>> Mike
>>
>> Mike,
>>
>> Different cameras were taken from different places under different
>> lighting conditions how can you say they are the same? For a comparison
>> to be able to be made that actually means anything all cameras would need
>> to be tested under the same conditions where as many variables as
>> possible were eliminated and that would include trying to use the exact
>> same lenses. I would expect the XTi to be better but he used a known very
>> sharp lens to do the tests on the XTi and a known average performer on
>> the K10D, also the shots for the XTi were very close shots where the K10D
>> and D200 for example were long range shots, how do you conclude that they
>> were the same??
>>
>>
> "Wayne J. Cosshall" <wayne@dimagemaker.com> wrote in message
> news:46229595$0$27883$afc38c87@news.optusnet.com.a u...
> > Hi Pete,
> >
> > I think you are missing the point a bit, these are explicitly image
> > noise tests, not lens tests, or sensor resolution tests. I do believe
> > you can make reasonable judgments about image noise from tests like
> > these in the real world.
>
> If you believe that different lenses will have no affect on apparent noise
> then my time here is wasted and I will move on.
Why would different lenses affect apparent noise, all other things being
equal?
Pentax K10D daylight image noise test 
Linear Mode
