From: Jufì on

"Scott W" <biphoto(a)hotmail.com> wrote in message
news:f19d17ee-9edb-4924-bd10-32460d231f02(a)d77g2000hsb.googlegroups.com...


What has been shown is that for the same number of pixels larger
pixels win. What has not been shown, at least I have not seen it, is
that for the same sensor area larger pixels win, in fact for many
cases they clearly do not.

Take a FF sensor, 10 MP pixels will win over 1 MP, even though the 1
MP sesnor will have larger pixels. At some point however fewer pixels
will win, for example 100 MP will win on a FF sesnor over 1000 MP, by
the time the pixels are down to the size needed to fit 100 MP there
will be little gain in going smaller.

So somewhere there is the sweat spot, the 1Ds III has I believe 21MP,
I doubt this will be the max number we see. BTW Most people would
prefer the 21MP on the 1Ds III vs. the 11 MP on the 1Ds
====================================================

What about diminishing returns? At what point are the pixels so small that
they become virtually useless? Very odd excercise.

From: Rich on
On Jul 16, 8:07 pm, Jufì <bow...(a)mac.hom> wrote:
> "Scott W" <biph...(a)hotmail.com> wrote in message
>
> news:f19d17ee-9edb-4924-bd10-32460d231f02(a)d77g2000hsb.googlegroups.com...
>
> What has been shown is that for the same number of pixels larger
> pixels win.  What has not been shown, at least I have not seen it, is
> that for the same sensor area larger pixels win, in fact for many
> cases they clearly do not.
>
> Take a FF sensor, 10 MP pixels will win over 1 MP, even though the 1
> MP sesnor will have larger pixels.

Is that why some scientific CCDs have 23um pixels?
From: Bates on
On Jul 16, 8:25 pm, Rich <rander3...(a)gmail.com> wrote:
> On Jul 16, 8:07 pm, Jufì <bow...(a)mac.hom> wrote:
>
> > "Scott W" <biph...(a)hotmail.com> wrote in message
>
> >news:f19d17ee-9edb-4924-bd10-32460d231f02(a)d77g2000hsb.googlegroups.com....
>
> > What has been shown is that for the same number of pixels larger
> > pixels win. What has not been shown, at least I have not seen it, is
> > that for the same sensor area larger pixels win, in fact for many
> > cases they clearly do not.
>
> > Take a FF sensor, 10 MP pixels will win over 1 MP, even though the 1
> > MP sesnor will have larger pixels.
>
> Is that why some scientific CCDs have 23um pixels?

Exactly. Particularly cameras used for fluorescence applications
where the amount of available photons is generally very low - exposure
times are relatively long, gain is set fairly high and noise is a big
problem.

From: John Sheehy on
Paul Furman <paul-@-edgehill.net> wrote in news:t9efk.29672$co7.7823
@nlpi066.nbdc.sbc.com:

> John Sheehy wrote:
>> Paul Furman <paul-@-edgehill.net> wrote in
>> news:Ze6fk.14817$mh5.10460(a)nlpi067.nbdc.sbc.com:
>>
>>> Of course, the DSLR image is enlarged [approx] 3x!
>>>
>>> 7.18 x 5.32 mm
>>> 24 x 18 mm
>>
>> That's the point, or at least part of it.
>
> For stacked astronomy data capture that may be useful, I'm not sure
> about normal daylight hand held still photos though. Or high contrast
> scenes needing dynamic range.

I'm not sure what you're trying to say here. What is "that"? My "that"
was the upscaling factor. If you're talking about stacking images with
sub-original-pixel alignment, yes, that is useful. You get higher
resolution detail, albeit at a low contrast, and if your SNR is low
enough, and you have the bit depth, you can sharpen it to good effect.
However, that is not why I upscaled the 400D here. It was to show how
the two different pixel densities compared, resolving the same area of a
focal plane, not only in resolution, but in noise. The 400D has one of
the lowest read noises in the industry at ISO 100, just behind the D3 and
the 1-series Canons by about 1/3 to 1/2 stop; much better than anything
fom Nikon/Sony CCD, the D2X, or any other MFR's DSLR except the
exceptional Pentax K10D. Yet, it can't touch the tiny 2 micron pixels of
the FZ50 here, which have almost exactly the same read noise relative to
absolute signal at ISO 100 as the 400D, at the pixel level. With 8.35x
as many pixels per unit of area, the effective read noise factors down by
the square root of that, to about 35% the read noise of the 400D.



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John P Sheehy <JPS(a)no.komm>
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From: John Sheehy on
"Jufi" <bowser(a)work.com> wrote in
news:e3lfk.31$X6.8(a)bos-service2b.ext.ray.com:

> Uh, OK. So why not compare cameras with the same size sensors but
> different numbers of pixels?

Do you have any idea how hard it is to find RAW data from two different
cameras of the exact same scene, with the exact same lighting, and the
exact same perspective point and exposure, and same real focal length? I
can not depend on other people; other people do not do things right.
They will vary something; probably a few things. I must work with what I
have. Besides, there is *VERY* little range in pixel pitch amongst
sensors of the same size, especially of the same technology era. The
results could be written off to small differences in support electronics,
quaantum efficiency, etc. You really need to compare *grossly* different
pixel sizes (preferably of the same era) to get the most meaningful
insight into differences of pixel pitch.

Nevertheless, it might be interesting to compare cameras from different
eras. A Canon 1D (the original, or "mk1") would probably look about as
bad as a DSLR can in a comparison like this. Its only savior is the
total sensor area.

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John P Sheehy <JPS(a)no.komm>
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