From: Roger N. Clark (change username to rnclark) on
John Sheehy wrote:

> Paul Rubin <http://phr.cx(a)NOSPAM.invalid> wrote in
> news:7x1wjzr5zg.fsf(a)ruckus.brouhaha.com:
>
>>I don't see how the 1Dmk3 does better given the various observations
>>that the 20D's low light performance is limited basically by photon
>>noise.
>
> It is a widely held belief that current cameras are limited mainly by
> photon noise, and Roger Clark's work is often quoted and referenced to
> support it, but I, for one, don't believe it. I believe that photon noise
> is a relatively pleasant-looking noise, and it is ruined by patterned read
> noises (both blackframe offset, and scalar illumination noises), which have
> much more visual power than the randomly-distibuted poisson shot noise.

Photon noise has a unique signature: it follows a square root dependence
on signal strength. You may not believe my results, but then how do you
explain all the other testing from the sensor manufacturers, university
testing, and other amateur astronomers testing that come to the
same conclusion and get the same results?
What noise source would you advocate that shows a square root dependence?
Why would the expected photon noise agree with derived quantum
efficiencies that agree with published QE levels?

Sure at the very low end, read noise, A/D quantization and pattern noise
is present, and that is also shown in the online test reports, but that
is usually below the level most people work at, and it is also
easily calibrated out for those who want to work at the lower levels
(e.g. astrophotographers. The implications of the 1D Mark III specs
imply significant improvements in this area too.

> That said, Canon does claim less wasted space on the sensor (higher fill
> factor) over the mkII, and greater quantum efficiency,

I didn't see any claim in increased quantum efficiency.
Efficiency due to fill factor and micro-lens improvements perhaps,
but not device quantum efficiency (although I would be happy
if I'm wrong here).

For those just joining, some relevant references on the subject:
http://www.clarkvision.com/imagedetail/index.html#sensor_analysis

Summary of data from many sources and also many references:
http://www.clarkvision.com/imagedetail/digital.sensor.performance.summary

Roger
From: ASAAR on
On 08 Mar 2007 19:26:39 -0800, Paul Rubin
<http://phr.cx(a)NOSPAM.invalid> wrote:

> Is there a feasible way to remove the Bayer filter from a DSLR sensor?

Would the Kodak DCS Pro 14n do? In a post from last July, a
Bystander giveth thusly:

> The 14 megapixel images it produces contain appreciably more
> information, as expressed in detail, colour, brightness range and so on
> than the old Kodachrome 25 slides in my library that I produced with the
> same lenses. They will reproduce excellently on A4 glossy magazine stock
> with as fine a screen lpi as you want.

but in concluding, all too quickly taketh away:

> My main anxiety about the Pro 14n, incidentally, is whether or not the
> batteries for it will still be available for the life of the camera. Use
> it in the right circumstances and the results are great -- but issues
> like slow startup, horrid noise levels in low light and surprising moire
> effects -- you wouldn't get that with Kodachrome -- easily justify the
> camera's discontinuance.

From: Paul Furman on
ASAAR wrote:

> Paul Rubin wrote:
>
>>Is there a feasible way to remove the Bayer filter from a DSLR sensor?

As in B&W?


> Would the Kodak DCS Pro 14n do? In a post from last July, a
> Bystander giveth thusly:

Is this monocrome?

>>The 14 megapixel images it produces contain appreciably more
>>information, as expressed in detail, colour, brightness range and so on
>>than the old Kodachrome 25 slides in my library that I produced with the
>>same lenses. They will reproduce excellently on A4 glossy magazine stock
>>with as fine a screen lpi as you want.
>
> but in concluding, all too quickly taketh away:
>
>>My main anxiety about the Pro 14n, incidentally, is whether or not the
>>batteries for it will still be available for the life of the camera. Use
>>it in the right circumstances and the results are great -- but issues
>>like slow startup, horrid noise levels in low light and surprising moire
>>effects -- you wouldn't get that with Kodachrome -- easily justify the
>>camera's discontinuance.
From: ASAAR on
On Fri, 09 Mar 2007 06:53:49 GMT, Paul Furman wrote:

>> Would the Kodak DCS Pro 14n do? In a post from last July, a
>> Bystander giveth thusly:
>
> Is this monocrome?

Monochrome?? The Kodak DSLRs (IIRC) did away with the AA filters,
which allowed them to produce very sharp images, but which had
negative side effects, such as a tendency to produce more noticeable
moire, and some "stair step" artifacts by straight edges. There was
also a version of the Kodak that used a Canon body, the last one
being made by Sigma when Canon declined further participation. I
don't know if the Sigma version was or wasn't sold, just having read
about it in an article that was an extended "hands on" review of the
Nikon body version which had been used by the reviewer for several
months.


>>>The 14 megapixel images it produces contain appreciably
>>> more information, as expressed in detail, colour, . . .

Nope, not monochrome. :)

From: nospam on
In article <7132v2t57hjkvvh49egpfmamd8ng2vhpqb(a)4ax.com>, ASAAR
<caught(a)22.com> wrote:

> There was
> also a version of the Kodak that used a Canon body, the last one
> being made by Sigma when Canon declined further participation. I
> don't know if the Sigma version was or wasn't sold, just having read
> about it in an article that was an extended "hands on" review of the
> Nikon body version which had been used by the reviewer for several
> months.

i saw someone using one about a year ago, so they've sold at least one.