Why not make the sensor larger?

Neil Harrington wrote:
"David J. Littleboy" wrote in message
...
"Neil Harrington" wrote:
"Philip Homburg" wrote:
There is for DoF and total number of photons (assuming equal total
number
of pixels).
Differences in those things, yes. But the f/ number still doesn't change.
In the film days, everyone used the same "sensor" (well, set of sensors)
regardless of format size.

That meant that the f/number abstraction made sense, since it told you the
flux per unit area of film, and you knew how film responded to flux per
unit area.

But it makes less sense for dcams. The FZ20 folks think they have a 450mm
f/2.8 lens, when the flux per pixel is a fraction of what the 30D sees
from a 300mm f/5.6 zoom.

The flux *per pixel*, yes. The "flux per unit area of film" as you put it
remains the same when you replace the film with an electronic sensor.

If correct exposure with a 30D at, say, ISO 100 is f/2.8 at 1/250, then with
an FZ20 at ISO 100 it's still f/2.8 at 1/250 (assuming of course the ISO
numbers are really what they say they are). How could it be otherwise?

Neil

Neil,
The flux per pixel changes between camera sizes because
the area of the pixel changes. That is the main factor
that is different from film days. Like you say, the
photons / area from an extended source stays they same,
but the area of the pixel is larger in the larger sensor
camera. More at:

The f/ratio Myth and Digital Cameras
http://www.clarkvision.com/photoinfo/f-ratio_myth

Roger

In article , says...

Multiple reads are irrelevant.

They are, because they increase the dynamic range.
--

Alfred Molon
------------------------------
Olympus 50X0, 7070, 8080, E3X0, E4X0 and E5X0 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site

[A complimentary Cc of this posting was sent to
Roger N. Clark (change username to rnclark)
], who wrote in article :
converted. You don't get more photons by multiple reads
of the chip.

??? By reading N times (and recharging the sensel in between), you
can collect N*FullWell photons.

Hope this helps,
Ilya

In article , Alfred Molon
writes
In article ,
says...

As David says, 4/3 is a completely lost opportunity, a conclusion that
made me, reluctantly, give up on Olympus some time ago. The sensor is
just too small to compete with the conventional 1.5 and 1.6 crops, let
alone FF, for noise and sensitivity at any given resolution while the
lens mount and design makes the camera too large to take a significant
share of the compact P&S market.

Hmmm... there is not much size difference between 4/3 and APS-C.
Increasing the size from 4/3 to APS-C does only give a slight noise
performance increase. And full frame lenses are eight times as heavy as
4/3 lenses for a specific angle of view and max aperture.

Now you are just being ridiculous Alfred!

Cite one single example of an Olympus 4/3 lens which weighs 8x less than
its equivalent FULL FRAME lens from the Olympus OM series.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

"Bill Funk" wrote in message
...
On Wed, 20 Jun 2007 16:43:44 -0400, "Neil Harrington"
wrote:


"Bill Funk" wrote in message
. ..
On Tue, 19 Jun 2007 11:49:47 -0400, "Neil Harrington"
wrote:

The term "subbing" is new to me. I just saw it in another post this
morning
for the first time. What's "subbing"?

Neil

Maybe this is part of your provblem: an inability to learn on your
own.
Are you aware of Google, and how to use it to search for things on the
Internet?
A hint: if you put "define: subbing" (sans quotes) into Google's
search box, it will find quick definitions for you.
You could even put, for example, "crop factor" (again, sans quotes)
into that same search box and find just how many respected sites
disagree with you on the usage of that term.
Of c ourse, I doubt this will change your mind; it must be open to new
things first.

Bad time of the month for you, Bill?

Neil

No, just trying to let you know that your ignorance can be easily
cured.

Why, did your PMS cure yours?

Neil

ASAAR wrote:
On Wed, 20 Jun 2007 16:57:09 -0400, Neil Harrington wrote:

Putting a backwards president into the oval office was also one of
our nation's stupider decisions.
Given the choices we were given at the time, it wasn't so stupid. Bush did
put two good SCOTUS justices in, remember. I.e., justices who will rule on
constitutionality according to what the Constitution actually says, rather
than what they'd like it to say instead.

You've got that exactly backwards, as confirmed by recent votes.


I shudder to think of what any Democratic president would have given us.

Something other than a preemptive war, mendaciously explained by
those higher-ups that were out to do what they wanted irregardless
(heh!).


And he has given us tax cuts, which are all to the good.

For the offshore bank account set.


Other than that, he's been quite a disappointment to conservatives generally.

Heck, I thought that as a draft dodger, der Shrub would have made
a fine POTUS. What possibly could have went wrong?

I think NH is misunderestimating the damage done by W.
Allen

"ASAAR" wrote in message
...
On Wed, 20 Jun 2007 16:57:09 -0400, Neil Harrington wrote:

Putting a backwards president into the oval office was also one of
our nation's stupider decisions.

Given the choices we were given at the time, it wasn't so stupid. Bush
did
put two good SCOTUS justices in, remember. I.e., justices who will rule
on
constitutionality according to what the Constitution actually says,
rather
than what they'd like it to say instead.

You've got that exactly backwards, as confirmed by recent votes.

Baloney. What recent votes? SCOTUS hasn't "discovered" any new rights or
privileges written in invisible ink since Roberts and Alito have been on the
court.



I shudder to think of what any Democratic president would have given us.

Something other than a preemptive war,

Maybe, maybe not. Remember most of the Democratic congresscritters voted for
that war, though of course "the next JFK from Massachusetts" (as he styled
himself) voted both for and against it, typical of his position on most
issues.


mendaciously explained by
those higher-ups that were out to do what they wanted irregardless
(heh!).

That's true.



And he has given us tax cuts, which are all to the good.

For the offshore bank account set.

For everybody. "Liberals" (as American leftists call themselves for some
unfathomable reason) love to criticize Republican "tax cuts for the rich,"
and I guess they keep doing this because their base likes to hear it over
and over. But Bush's tax cuts benefited all of us, just as Reagan's did --
and the Reagan tax cuts got the same griping from the Democrats. Tax cuts
are good for the economy too. Remember that the expanding economy for which
Clinton was so quick to take credit actually started in 1983, the early
Reagan years.

Let's face it, Democrats just love to tax, and become really cranky when
anyone interferes with that. Remember Clinton's promise that his tax
increases would be "only for the wealthy"? It turned out that "the wealthy"
meant most people making $30,000 or more -- though wealthy Democrats manage
to keep plenty of tax loopholes for themselves.



Other than that, he's been quite a disappointment to conservatives
generally.

Heck, I thought that as a draft dodger, der Shrub would have made
a fine POTUS. What possibly could have went wrong?

He wasn't a draft dodger. He served in the Air National Guard, and with some
expectation of pulling a tour in Vietnam, as other ANG pilots did. You've
been listening to too many enraged leftist loonies.

You may be thinking of Clinton, who signed up for ROTC to avoid the draft,
reneged on that and then fled the country instead -- joined antiwar
activists in England, didn't he?

Neil

"acl" wrote in message
oups.com...
On Jun 21, 1:03 am, "Neil Harrington" wrote:
"acl" wrote in message


Given the amount of effort you put into arguing against the term "crop
factor", I'll be particularly amused if DJL resorts to his usual
putdowns of "crop fan" and the like in response to your post

He usually puts down "crop fan"? What's a "crop fan"? (Sorry, I only read
a
small fraction of the posts here and I guess I miss a lot.)


A fan of cameras with a crop factor larger than 1

Oh.


[Sorry for the
use of the c-word, but you did ask].

That's OK. I'll be more cautious next time. :-)

Neil

"Roger N. Clark (change username to rnclark)" wrote in
message ...
Neil Harrington wrote:
"David J. Littleboy" wrote in message
...
"Neil Harrington" wrote:
"Philip Homburg" wrote:
There is for DoF and total number of photons (assuming equal total
number
of pixels).
Differences in those things, yes. But the f/ number still doesn't
change.
In the film days, everyone used the same "sensor" (well, set of sensors)
regardless of format size.

That meant that the f/number abstraction made sense, since it told you
the flux per unit area of film, and you knew how film responded to flux
per unit area.

But it makes less sense for dcams. The FZ20 folks think they have a
450mm f/2.8 lens, when the flux per pixel is a fraction of what the 30D
sees from a 300mm f/5.6 zoom.

The flux *per pixel*, yes. The "flux per unit area of film" as you put it
remains the same when you replace the film with an electronic sensor.

If correct exposure with a 30D at, say, ISO 100 is f/2.8 at 1/250, then
with an FZ20 at ISO 100 it's still f/2.8 at 1/250 (assuming of course the
ISO numbers are really what they say they are). How could it be
otherwise?

Neil

Neil,
The flux per pixel changes between camera sizes because
the area of the pixel changes.

Sure.

That is the main factor
that is different from film days. Like you say, the
photons / area from an extended source stays they same,
but the area of the pixel is larger in the larger sensor
camera.

I've got that all right, but the fact remains, for any given ISO and scene
brightness the f-stop and shutter speed remain the same regardless of pixel
size, correct? Otherwise what meaning would the ISO number have?


More at:

The f/ratio Myth and Digital Cameras
http://www.clarkvision.com/photoinfo/f-ratio_myth

I've read that and it's very interesting, Roger, but I'm not sure you make a
case for its being a myth.

Neil

On Thu, 21 Jun 2007 10:52:04 -0400, Neil Harrington wrote:

Heck, I thought that as a draft dodger, der Shrub would have made
a fine POTUS. What possibly could have went wrong?

He wasn't a draft dodger. He served in the Air National Guard, and with
some expectation of pulling a tour in Vietnam, as other ANG pilots did.
You've been listening to too many enraged leftist loonies.

Nonsense. Bush was given preferential assignment to a "Champagne"
unit of the Air National Guard, one which was unlikely to be used
(and wasn't) in Vietnam. Unlike today, where Bush's war depends on
the heavy use of the National Guard, it was a different when he was
young, irresponsible, and best described as a privileged brat.

During the 1968–1974 period, Presidents Johnson and Nixon decided
against calling up National Guard units for service in Vietnam. As a
result, National Guard service was widely portrayed as a way to avoid
combat. The waiting list for the Guard at that time was extremely long,
and there have been charges that young men from influential families
were improperly moved to the top of the list (a similar accusation was
leveled at Dan Quayle, who served in the Indiana National Guard, and
was vice-president in 1989–93, when Bush's father was president).

According to various media outlets, Bush jumped to the top of a list of
over 500 applicants for his position as a pilot despite receiving the
minimum passing score (25) on the pilot entrance aptitude test and
listing no other qualifications.[3] Other reports indicated that although
there were many candidates interested in weekend enlisted duty, there
were fewer, if any, people who were both sufficiently educated to qualify
for an officer pilot position and willing to commit to the more than one
year of full-time service required of Air National Guard pilots.[4]
Ben Barnes, the former Speaker of the Texas House of Representatives
and Lieutenant Governor of Texas, stated under oath that he had called
the head of the Texas Air National Guard, Brig. Gen. James Rose, to
recommend Bush for a pilot spot at the request of Bush family friend
Sidney Adger.

In a 1994 interview, Bush stated that he joined the Guard because "I
was not prepared to shoot my eardrum out with a shotgun in order to
get a deferment. Nor was I willing to go to Canada. So I chose to better
myself by learning how to fly airplanes."[6]

The unit in which Bush served was known as a "Champagne unit," where
the scions of the Texas aristocracy could avoid combat duty with relatively
few demands on their time. Serving in that unit with Bush were the sons
of three prominent men: Democratic Governor John Connally, Democratic
Senator and future Vice-Presidential nominee Lloyd Bentsen, and
Republican Senator John Tower, as well as seven members of the Dallas
Cowboys professional football club, and a man named James R. Bath,
who would become a longtime friend of Bush's.
. . .
A column in the Birmingham News (Alabama) elicited memories from
people who remembered Bush when he was in Alabama, working for the
Blount campaign: "None have specific recollections about Bush and the
National Guard. Some heard he was serving but never saw for themselves."
Opinions of him during this time ranged from good (amiable, well liked,
and fond of sports) to bad (bragging about drinking and allegations he
trashed a cottage where he was living). Winton Blount's son Tom said
"He was an attractive person, kind of a 'frat boy.' I didn't like him."
Winton Blount's nephew C. Murphy Archibald, who also worked on the
Blount campaign, said that Bush also made an impression on the
"Blue-Haired Platoon," a group of older Republican women working for
Blount. Behind his back they called him "the Texas soufflé," Archibald
said, because he was "all puffed up and full of hot air."[


http://en.wikipedia.org/wiki/George_...ce_controversy


You may be thinking of Clinton, who signed up for ROTC to avoid the
draft, reneged on that and then fled the country instead -- joined antiwar
activists in England, didn't he?

Nope. He didn't flee the country to join antiwar activists. As
the winner of a Rhodes Scholarship he went to England to attend
Oxford University. And if that helped him to escape the draft, then
as Bush previously said, it was a better solution than getting a
deferment by using a shotgun to "shoot my eardrum out".