From: John Sheehy on
John O'Flaherty <quiasmox(a)yeeha.com> wrote in
news:g5bs7490188ng5i849tmko3ma6aat0sh19(a)4ax.com:

>>Of course, such a test would give a result already expected by almost
>>anyone who knows anything at all about digital imaging, but would tell
>>us absolutely nothing about the effects of pixel *density*; only about
>>sensor size.

> That clarifies it. In your post, you said that "the bigger pixels of
> the DSLR are inferior compared to the higher pixel density of the
> small sensor camera"; apples and orange juice.

What I am demonstrating needs to be demonstrated. There is too much
nonsense out there circulating as fact, suggesting that the more pixels
you "stuff" into a given sensor size, the noisier the images get, the
less DR they have, etc, etc. This clearly shows that this is not true,
that pixels covering less of the focal plane each can currently do much
better than big pixels, at representing the area that they are
responsible for.

This test, however, is not about DR, per se, as the 400D still has some
more headroom than the FZ50 here. It is more about absolute sensitivity
in this case, although the usable DR should still be better with the
smaller pixels.

--

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John P Sheehy <JPS(a)no.komm>
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From: John Sheehy on
Blinky the Shark <no.spam(a)box.invalid> wrote in
news:pan.2008.07.16.06.50.09.925750(a)thurston.blinkynet.net:

> John Sheehy wrote:
>
>> Scott W <biphoto(a)hotmail.com> wrote in
>> news:fbef99b9-2adc-429e-96bc-9f46ec665b7f(a)x41g2000hsb.googlegroups.com
>> :
>>
>>> Do we really need more cross posting?
>>
>> I generally don't mind relevant cross-posting, but that comes from
>> using Agent. I am using XNews now, and the method of cross-post
>> management in XNews seems a bit inferior and dangerous, so I wind up
>> seeing a lot of things twice.
>
> Then you don't know how to use Xnews.

No, I don't, and that comes from very bad experiences with it, poor
documentation, and an unwillingness to experiment. I have found that
keystrokes in Xnews have irreversible consequences.

The way I understand it, I have to tell one newsgroup that I am "caught
up" for cross-post management to work in the next group I read. I am
never caught-up, so that is not an option.

A properly-functioning newsreader will automatically omit cross-posts
from all but one group, and an ideal one would be aware that I have read
it in another group, and mark it as read in the current one.

--

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John P Sheehy <JPS(a)no.komm>
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From: John Sheehy on
rfischer(a)sonic.net (Ray Fischer) wrote in news:487d881a$0$17222
$742ec2ed(a)news.sonic.net:

> John P Sheehy <jps(a)no.kom> wrote:
>>I've made a direct comparison of RAW data per unit of area in the deep

> "per unit area"

> In other words, if you know what results you want to get then you can
> adjust your measurement to get those results.

I made a direct comparison of combined read and shot noise relative to
absolute signal, and resolution, of two different pixel densities capturing
the same area of a focal plane from the same scene with the same focal
length and li9ght intensity.

If you think that this is some juvenile praise of the FZ50, you are a blunt
idiot, on a witch hunt for fanboys.

--

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John P Sheehy <JPS(a)no.komm>
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From: John Sheehy on
Bates <nw1008(a)gmail.com> wrote in
news:2917f6ca-48e7-4c2e-a8d2-b0906a2dcfdb(a)l42g2000hsc.googlegroups.com:

> On Jul 15, 9:22 am, John P Sheehy <j...(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
>>
>> --
>> John Sheehy
>
> It's an interesting test but it there are too many other variables
> involved here which are causing problems. For one (and I'm not saying
> you have the equipment, resources or money to do this test), if you
> want to really only compare the effect of pixel density which is what
> your subject line states, then I would think the better test is to
> line up a 350D and 400D and a 450D - all of which have the exact same
> sensor size, but differ in pixel density only
> (http://www.dpreview.com/
> reviews/compare_post.asp?method=sidebyside&cameras=canon_eos400d
> %2Ccanon_eos450d
> %2Ccanon_eos350d&camuser=canon_eos400d&camuser=canon_eos450d&camuser=ca
> non_eos350d&show=all). Then you can use the exact same lens
> etc....compare the exact same sensor size, and only worry about pixel
> density.

The pixel pitch difference between them is too small to make any
meaningful comparison, in light of the other variables. The 450D would
do best, and the 350D, a little worse than the 400D. Whoopedy do dah
ding! You could write that off as incremental increases in microlens
efficiency, minor read noise improvements, etc, as far as noise goes, and
pixel pitch and the lack of a strong AA filter in the 450D as far as
resolution goes. The doomsday forecast for pixel pitch, however,
suggests that going beyond a certain point in pixel density will cause an
increase in noise and loss of DR, but it is not happening, nowhere even
close to current pixel densities (if ever), and that is the point of my
demsonstration.

Anyone with any amount of experience in these matters would recognize
that even a magic lens with no softness of any kind

--

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John P Sheehy <JPS(a)no.komm>
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From: Blinky the Shark on
John Sheehy wrote:

> Blinky the Shark <no.spam(a)box.invalid> wrote in
> news:pan.2008.07.16.06.50.09.925750(a)thurston.blinkynet.net:
>
>> John Sheehy wrote:
>>
>>> Scott W <biphoto(a)hotmail.com> wrote in
>>> news:fbef99b9-2adc-429e-96bc-9f46ec665b7f(a)x41g2000hsb.googlegroups.com
>>> :
>>>
>>>> Do we really need more cross posting?
>>>
>>> I generally don't mind relevant cross-posting, but that comes from
>>> using Agent. I am using XNews now, and the method of cross-post
>>> management in XNews seems a bit inferior and dangerous, so I wind up
>>> seeing a lot of things twice.
>>
>> Then you don't know how to use Xnews.
>
> No, I don't, and that comes from very bad experiences with it, poor
> documentation, and an unwillingness to experiment. I have found that
> keystrokes in Xnews have irreversible consequences.

Have you ever used news.software.readers for assistance? The user is
directed ther in The Fine Manual. It's usually the first group I
read, and I have a large section of Xnews stuff on my own web site.

http://blinkynet.net/comp/ndx_windows.html#xnews

Also, there are one or two other instuctional files in the Xnews
directory. Have you read that/those?

And you're using a several-years-old version of Xnews. It's been updated
18 times since what you have.

http://blinkynet.net/comp/xnewsarch/index.html

How to update (download one file and copy it into your Xnews directory;
that's it). Here:

http://blinkynet.net/comp/xnewsrels.html

> The way I understand it, I have to tell one newsgroup that I am "caught
> up" for cross-post management to work in the next group I read. I am
> never caught-up, so that is not an option.
>
> A properly-functioning newsreader will automatically omit cross-posts

We have differing views on "properly-functioning newsreader[s]". I've
evaluated Agent, for instance, twice. It sucked both times, and was
discarded. Even with the recent revisions, it still can't do a reasonably
good job of filtering/scoring; for instance it requires one to run a
separate local news server/proxy just to kill Google Groups posts, whereas
a properly-functioning newsreader can very easily do that simply by
filtering on the Message-ID header that every post contains. I have,
IIRC, eight news clients installed, configured, and ready for use (mostly
to help others or answer questions); I think I'm fairly well versed on
what features are out there. ;)

> from all but one group, and an ideal one would be aware that I have read
> it in another group, and mark it as read in the current one.

I always figured that's what Xnews was doing (it's been my preferred
Windows news client for several years) -- but, then, when I finish up with
a group, I always exit with a catch-up. Check into news.software.readers
and see if what you wish can be done; there are wizards there. I hope to
see you there. Or, at least, a modern version of Xnews in your
User-Agent headers soon. :)


--
Blinky
Killing all posts from Google Groups
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