From: cjcampbell on
On Apr 2, 3:44 pm, "David J. Littleboy" <davi...(a)gol.com> wrote:
> "ASAAR" <cau...(a)22.com> wrote in message
>
> news:nes213dcj5vf5thoi3hm6b6l91qa14gpcg(a)4ax.com...
>
> > On 2 Apr 2007 12:36:31 -0700, cjcampbell wrote:
>
> >>> Interesting twist on physics ... excitement = creation ;-)
>
> >> A good April Fool's joke should have some inaccurate physics in it.
> >> Plausible, but inaccurate.
>
> > But then it would have irreproducable results, not good enough to
> > justify submitting to a journal! :)
>
> There's always the Journal of Irreproducible Results.
>
> http://www.jir.com/
>

I have been reading them off and on for more than 35 years. I think my
favorites of all time were the mathematical proof that all obtuse
angles were equal (and therefore all rates of spin were equal) and
"The Inheritance Factor of Death." Also, every photographer could
probably use a darkbulb at some time or another.

From: John Sheehy on
"David J. Littleboy" <davidjl(a)gol.com> wrote in
news:eus134$9h8$2(a)nnrp.gol.com:

> "John Sheehy" <JPS(a)no.komm> wrote:

>> What he's saying is that the shot noise in each layer in each RGB
>> sensel will be higher by that factor, because only 1/3 of the photons
>> are captured
>> in each level.

> Nope. I'm saying the well depth will be 1/3, so the maxmum number of
> photons counted will be 1/3.

I fail to see the difference.

--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS(a)no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
From: David J. Littleboy on

"John Sheehy" <JPS(a)no.komm> wrote:
> "David J. Littleboy" <davidjl(a)gol.com> wrote:
>> "John Sheehy" <JPS(a)no.komm> wrote:
>
>>> What he's saying is that the shot noise in each layer in each RGB
>>> sensel will be higher by that factor, because only 1/3 of the photons
>>> are captured in each level.
>
>> Nope. I'm saying the well depth will be 1/3, so the maxmum number of
>> photons counted will be 1/3.
>
> I fail to see the difference.

I'm talking about the maximum signal that can be recorded by the charge
storage device in the pixel. It's reduced by 1/3 by the requirement that you
have to have three charge storage devices in the same area of silicon (each
pixel).

That doesn't have anything to do with how many photons (or what percentage
of photons) one captures at each level.

David J. Littleboy
Tokyo, Japan


From: Bill Funk on
On 2 Apr 2007 07:54:42 -0700, "cjcampbell"
<christophercampbell(a)hotmail.com> wrote:

>On Apr 2, 7:27 am, "Thomas T. Veldhouse" <veld...(a)yahoo.com> wrote:
>> J. Clarke <jclarke.use...(a)cox.net> wrote:
>> > Thomas T. Veldhouse wrote:
>> >> nospam <nos...(a)nospam.invalid> wrote:
>> >>> FOR IMMEDIATE RELEASE
>>
>> >>> 37 Megapixel Direct Image Sensor brings the revolutionary patented
>> >>> Foveon X3 Full-Color Technology to Nikon's forthcoming full frame
>> >>> Digital SLR, the Nikon D3F.
>>
>> >> You wasted a lot of time on this silly joke.
>>
>> > Not nearly as much as Google did on _their_ April Fool joke. And then
>> > there was Trump's . . .
>>
>> While the OPs wasn't all that funny or unanticipated, I am interested to find
>> out what Google's and Trump's joke was ;-)
>
>Google was offering unlimited free internet access through your toilet.

Google also offered to print any email you wanted and mail it to you.

--
THIS IS A SIG LINE; NOT TO BE TAKEN SERIOUSLY!
White House aide Karl Rove brought
down the house at the correspondents'
dinner Wednesday when he performed
a rap song as MC Rove. The number
was awkward from the start. He asked
for a downbeat and the deejay read
him the president's approval rating.
From: acl on
On Apr 3, 12:01 am, John Sheehy <J...(a)no.komm> wrote:
> "acl" <achilleaslazari...(a)yahoo.co.uk> wrote innews:1175535531.207412.313090(a)e65g2000hsc.googlegroups.com:
>
> > On Apr 2, 7:52 am, "David J. Littleboy" <davi...(a)gol.com> wrote:
>
> >> Measuring three colors at each point costs you sqrt(3) in dynamic
> >> range and noise and makes raw files three times larger.
>
> > Why do you say sqrt(3)? I do not remember seeing any data about
> > saturation capacities in electrons of these detectors.
>
> What he's saying is that the shot noise in each layer in each RGB sensel
> will be higher by that factor, because only 1/3 of the photons are captured
> in each level.

But this is the same with CFAs, it's just that you absorb the extra
photons in the filter without detecting them.

> For the Foveon used in the SD9 and 10, that is probably an
> issue, as color has to be converted from very unsaturated RAW data.

If you look at absorption curves with depth (given in papers put out
by Foveon themselves), it's quite obvious why colour separation is not
so good. Apparently also there are problems with the red channel which
necessitates more sharpening (maybe some sort of charge diffusion
process-but what do I know?).

> If
> that were not an issue, however, I don't think the shot noise would be much
> of an issue, because the Bayer shot noise, though less in each sample, is
> bigger in height and width, making it just as strong, visually. This can
> actually be emulated - I'll put it on my list of things to try when I find
> lots of time.
>

I don't understand this paragraph. I'll think a bit about it.

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