From: Floyd L. Davidson on
John Sheehy <JPS(a)no.komm> wrote:
>> Do you think there might be a problem with your methodology?
>
>Not at all; this is as close to "all other things being equal" as we can
>expect to get, for comparing the IQ effects of pixel density in light-
>starved situations. In all probability, the lens on the 400D has nowhere
>near the MTF of the lens in the FZ50, but even a B&W checkerboard pattern
>with 1-pixel tiles would be relatively soft blown up 289%.

That is just false.

The two different sensors, mounted behind the same lense
and getting identical processing (in camera as well as
post camera) would be the way to make "all other things
being equal" a valid statement.

If you think Nikon, Canon, Sony, et al are not doing exactly
that, I've got a bridge for sale that you'll enjoy testing.

And if you cannot do that, then you simply cannot expect
your tests to be considered seriously.

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd(a)apaflo.com
From: Scott W on
On Jul 15, 9:20 am, Jufí <b0w...(a)h0me.c0m> wrote:
> "John P Sheehy" <j...(a)no.kom> wrote in messagenews:Xns9ADC5F5E96172jpsnokom(a)199.45.49.11...
>
> > I've made a direct comparison of RAW data per unit of area in the deep
> > shadows of ISO 100 between the FZ50 (1.97 micron) and the 400D (5.7
> > micron).  Exposure is the same, same Av (f/4.5), same Tv (1/100), same
> > real
> > focal length (22mm), both shot at "ISO 100" pushed to ISO 13,500.  Large
> > crop is 100% for FZ50 (0.4MP), and small crop is 100% for 400D (0.05MP),
> > and the other two are the other camera scaled to the 100% crop of each.
> > As
> > I already knew, the bigger pixels of the DSLR are inferior compared to the
> > higher pixel density of the small sensor camera:
>
> >http://www.pbase.com/jps_photo/image/100092629
>
> I suggest you call the NY Times or Scientific American since your expirement
> completely contradicts what every tester has shown to date. Do you think
> there might be a problem with your methodology? How about just shooting the
> same scene, same angle of view, and enlarging each image to 100%? Too
> complicated?
>
> Sorry, but larger pixels always win the day.

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

Scott
From: Jufí on

"John Sheehy" <JPS(a)no.komm> wrote in message
news:Xns9ADCBFE131BC0jpsnokomm(a)199.45.49.11...
> Juf� <b0wser(a)h0me.c0m> wrote in news:UL6fk.316$6O4.307(a)trnddc06:
>
>> I suggest you call the NY Times or Scientific American since your
>> expirement completely contradicts what every tester has shown to date.
>
> What were they testing, *exactly*? Did they have access to the RAW data,
> or just JPEGs and conversions?
>
>> Do you think there might be a problem with your methodology?
>
> Not at all; this is as close to "all other things being equal" as we can
> expect to get, for comparing the IQ effects of pixel density in light-
> starved situations. In all probability, the lens on the 400D has nowhere
> near the MTF of the lens in the FZ50, but even a B&W checkerboard pattern
> with 1-pixel tiles would be relatively soft blown up 289%.
>
>> How about
>> just shooting the same scene, same angle of view, and enlarging each
>> image to 100%? Too complicated?
>
> No; too *irrelevant* to the issue of PIXEL DENSITY.
>
>> Sorry, but larger pixels always win the day.
>
> Sorry, but that's wrong. With a few exceptional situations (specifically
> read noise, but not shot noise, at ISOs 1600 and above, in a very small
> number of DSLRs), smaller pixels filling the same sensor area give better
> imaging. Larger pixels are only universally better when they are doing
> the same job; IOW, when they have the same imaging responsibility.

John, nothing you've posted here is correct. If you want, I'll shoot pix
using my G9 and 5D at ISO 1600, and post the 100% crops. Resolution of the
sensors is very close, only the size of the pixels is very different. It
will shot that smaller pixels simply cannot compete with larger pixels.
Unless I'm totally missing your point here...

From: Scott W on
On Jul 15, 2:29 pm, Jufí <b0w...(a)h0me.c0m> wrote:
> "John Sheehy" <J...(a)no.komm> wrote in message
>
> news:Xns9ADCBFE131BC0jpsnokomm(a)199.45.49.11...
>
>
>
>
>
> > Jufí <b0w...(a)h0me.c0m> wrote innews:UL6fk.316$6O4.307(a)trnddc06:
>
> >> I suggest you call the NY Times or Scientific American since your
> >> expirement completely contradicts what every tester has shown to date.
>
> > What were they testing, *exactly*?  Did they have access to the RAW data,
> > or just JPEGs and conversions?
>
> >> Do you think there might be a problem with your methodology?
>
> > Not at all; this is as close to "all other things being equal" as we can
> > expect to get, for comparing the IQ effects of pixel density in light-
> > starved situations.  In all probability, the lens on the 400D has nowhere
> > near the MTF of the lens in the FZ50, but even a B&W checkerboard pattern
> > with 1-pixel tiles would be relatively soft blown up 289%.
>
> >> How about
> >> just shooting the same scene, same angle of view, and enlarging each
> >> image to 100%? Too complicated?
>
> > No; too *irrelevant* to the issue of PIXEL DENSITY.
>
> >> Sorry, but larger pixels always win the day.
>
> > Sorry, but that's wrong.  With a few exceptional situations (specifically
> > read noise, but not shot noise, at ISOs 1600 and above, in a very small
> > number of DSLRs), smaller pixels filling the same sensor area give better
> > imaging.  Larger pixels are only universally better when they are doing
> > the same job; IOW, when they have the same imaging responsibility.
>
> John, nothing you've posted here is correct. If you want, I'll shoot pix
> using my G9 and 5D at ISO 1600, and post the 100% crops. Resolution of the
> sensors is very close, only the size of the pixels is very different. It
> will shot that smaller pixels simply cannot compete with larger pixels.
> Unless I'm totally missing your point here...-
The point he is making, with some trouble, is that for the same size
sensor more pixels are better, which is often, but not always, true.

Scott

From: John O'Flaherty on
On Tue, 15 Jul 2008 13:22:32 GMT, John P Sheehy <jps(a)no.kom> wrote:

>I've made a direct comparison of RAW data per unit of area in the deep
>shadows of ISO 100 between the FZ50 (1.97 micron) and the 400D (5.7
>micron). Exposure is the same, same Av (f/4.5), same Tv (1/100), same real
>focal length (22mm), both shot at "ISO 100" pushed to ISO 13,500. Large
>crop is 100% for FZ50 (0.4MP), and small crop is 100% for 400D (0.05MP),
>and the other two are the other camera scaled to the 100% crop of each. As
>I already knew, the bigger pixels of the DSLR are inferior compared to the
>higher pixel density of the small sensor camera:
>
>http://www.pbase.com/jps_photo/image/100092629

What happens if you compare subimages using the same number of pixels
to cover the same subject area, with, say, the same total illumination
falling on that subject area?

--
John