How to measure ISO

In article ,
Sandman wrote:

Eric Stevens:
Posting a list you have pinched from somewhere else without
explanation doesn't offer support for anything.

Sandman:
I made that list, from data from dpreview. Do you have a better
list? No? Then it is valid.

it doesn't work that way.

Sorry, you don't get to decide what "it" is in my comparison data.

i didn't decide.

a cherry-picked a list is not proof of *anything*. end of story.

furthermore, it's not valid solely because nobody else created a
different list.

it must stand on its own. and it doesn't.

nevertheless, i did provide a list that invalidated your claim.

Sandman:
Those are the MFT and FF cameras released since April 2013 as
listed by dpreview. Do you disagree with the list?

who cares. it's nothing more than a list of cameras made in the past
few years. big deal. that says *nothing* about photosite sizes.
nothing at all.

It says everything about photo site sizes between those cameras,

but not as a general rule.

that's what you don't get.

physics does not apply to only sensors made between 4/13 and 11/15. it
applies to *all* sensors.

that's beyond ****ed up.

if you
understand the physics.

*far* more than you do.

you've gotten *so* much wrong that i've lost track.

Sandman:
This is how proof works. One has a claim, one posts supporting
data, which remains valid until it has been invalidated. Merely
claiming it isn't valid is just nospam-like hot air.

claiming that a list of recent cameras is somehow proof of something
is beyond ludicrous. it's truly ****ed up.

Best endorsement I could ever get.

be glad that's what you got.

put simply: you're full of ****.

Ah, personal attacks, the trolls last resort when he's crying on the floor.

it's not a personal attack. it's a statement of fact.

what you've said is wrong. simple as that.

worse, you're too stubborn to admit it and learn something.

Eric Stevens:
Are you trying to say that a contemporary camera which has
smaller photosites has a smaller sensor?

Sandman:
No, all contemporary cameras with smaller sensors have smaller
photosites. This was obvious from my sentence above.

facts do not care what's contemporary and what's not.

When the fact concerns contemporary cameras, it does.

facts are not limited to only certain cameras.

either it applies to all sensors or it's void.

a single example is all that's needed to prove you wrong and several
have been provided.

snip empty claims and hot air from nospam

You've been doing this for twelve days now - making empty claim after empty
claim. It's like you're allergic to supporting your view.

it ain't just me.

*many* people have shown just how wrong you are during the 12 days.

you refuse to learn.

you're *so* ****ed up that you don't even realize just how wrong you
really are.

In article , Eric Stevens
wrote:

Sandman:
With a given exposure, a MFT sensors receives
(roughly) one fourth the amount of light as a FF sensor. If
you were to give the MFT sensor the same amount of total
light (I trust you are familiar with how to operate a camera
to give a sensor more light), the signal amplification will
be comparable.

False. Completely false.

So prove it wrong - merely blowing hot air in my general direction says
exactly
nothing.

I've already done so. nospam has done so. Alan Browne has done so.
Whisky Dave has done so. So too have other people whose names I can't
recall at the moment. This is not a topic where you can win by being
stubborn.

no ****.

savageduck, billw, and i think one or two others.

*all* of them have said the same thing, that sandman is wrong.

In article , Eric Stevens
wrote:


All my claims have been with equal focal length and f/stop.

Shouldn't you have scaled the focal length according to the crop
factor?

yes, and f/stop too. otherwise it's not equivalent.

Providing he scales the focal length, the f/stop is self-scaling.

yes and no.

people use a lens with an equivalent focal length, but they use the
same f/stop so that the exposure is the same.

for equivalency, the f/stop needs to scale with the focal length so
that the depth of field is the same, but in order to maintain the same
exposure, the iso of the larger sensor needs to be raised.

In article ,
Sandman wrote:

Sandman:
With smaller photo sites, found in smaller sensors,
each photo site receives less light and the signal needs to
be amplified more while reporting the same ISO value as a
larger sensor.

nospam:
smaller sensors *might* have smaller photosites.

Sandman:
Smaller sensors have smaller photo sites:

http://jonaseklundh.se/files/cameras_since_2013.png

except when they don't.

olympus e-1 and nikon d800.

2003 vs. 2012.

nikon d70 and nikon d800

2004 vs. 2012

canon 1d and sony 7r ii.

2001 vs. 2015

so what?

facts don't care about release dates.

3 examples that prove you wrong when only 1 was needed, and there are
way more than just those 3.

You really had to dig through the ages to find smaller sensor cameras with
bigger photo sites.

i didn't have to dig, not that it matters if i did.

what matters is that there exists an example that disproves your claim,
and there does.

the reality is that there *are* smaller sensors with larger photosites.
it's as simple as that.

what's really ****ed up is that you're *still* trying to weasel out of
it.

As you can see, I talk about contemporary cameras, and
comparing them. Few people would compare a Nikon D70 with a D800. But het,
semantics, right?

it's not semantics.

you made a statement which was incorrect, that smaller sensors have
smaller photosites.

when it became apparent it was wrong, you then changed it to be only
contemporary cameras to try to weasel out of not admitting that you
were wrong.

now that additional proof has been provided, you're *still* trying to
avoid admitting it.

the *only* reason someone would change it to contemporary cameras would
be if they knew all along that they were wrong and didn't want to admit
it. there's no other explanation that fits.

the laws of physics were not enacted three years ago.

the laws of physics existed long before there even were digital cameras.

Sandman:
More amplification leads to more noise, which is what
makes people think smaller sensors are noisier, when in
reality they aren't, they're just not receiving as much
light.

nospam:
you just said a smaller sensor needs more amplification,
resulting in more noise, which means smaller sensors are
noisier.

Sandman:
Indeed - since they are getting less light.

which means it's not due to amplification.

It means exactly that, since for them to produce an equally bright image at
the
same ISO value, the signal needs to be amplified more. If you give them the
same amount of total light, the signal need not be amplified more than on the
larger sensors, and you get an equally clean image.

nope

Which, incidentally, is exactly what I've been saying for the last 12 days,
and
something you still can't wrap your head around.

it's no more correct now than it was then.


nospam:
now you say they really aren't.

Sandman:
If they get the same amount of light.

which affects exposure.

Well, duh.

you're all over the map.

nospam:
make up your mind.

Sandman:
Learn to read.

take your own advice.

No need, I read just fine, thanks.

not from what i can tell.

Sandman:
If you give them the same amount of total light (i.e.
the same amount of light per photo site), the noise levels
are comparable to that of a larger sensor, while brightness
is the same. But, you have to adjust the ISO value down by the
crop factor squared (roughly).

nospam:
not quite, because the same amount of light on smaller
photosites would likely saturate them.

Sandman:
Incorrect.

nope.

it's *exactly* correct.

Incorrect, since your "likely" assumes a given amount of light, an amount
that
was not given or specifically stated. The same amount of light CAN saturate a
given photo site, but it's not "likely", since it's all up to the exposure.

nope to both. you're so confused.

smaller photosites will saturate with less light.

http://www.appuntidigitali.it/site/w...l-well-capacit
y1.jpg

simple physics.

a smaller photosite has a lower full well capacity which means it
will saturate with less light than a larger photosite.

simple physics.

Indeed - using supposed input data that was never specified, making the
"likely" another empty claim.

wrong. the input data is irrelevant. pick whatever input data you want.
it doesn't change anything.

a smaller photosite has a lower full well capacity and will saturate
sooner. period. end of story.

http://www.appuntidigitali.it/site/w...l-well-capacit
y1.jpg

think rain buckets. a smaller bucket holds less water than a larger
bucket.

Indeed, and that's the example that I used 12 days ago, and it flew past you
then as well.

it flew clear over *your* head because it proves you wrong, as noted
above.

in other words, your examples did not fly anywhere. they crashed and
burned.

We're talking about a given exposure, for example:

Contemporary FF sensor: 1/250, f.28 with an ISO of 800

Right, no problem there.

yes a problem. nix the contemporary bit. theory does not care when a
sensor was made.

cite megapixel count.

This will produce a given amount of light. Let's
assume it produces an even exposure over the sensor, a perfectly composed
image
that looks nice. Very well.

an even exposure over the sensor would be neutral grey.

Now do the exact same exposure on a contemporary MFT sensor.

again, contemporary does not matter.

either it's valid for everything or it's not.

if you have to cherry pick certain sensors then it's not valid, but you
won't ever admit that.

This will of course expose the same amount of light per unit area, but we
have
less unit areas, so not all light is being used.

nonsense.

all light is used.

Furthermore, the photo sites
are smaller, so each one gets slightly less signal.

that depends on how much smaller they are.

if the difference is only slightly less then there won't be much
difference in the noise.

another contradiction.

This means that when set to ISO 800, the MFT sensor with its smaller photo
sites will have to amplify its signal *more* to achieve the same level of
brightness that the larger sensors does.

nope.

This leads to noise, so the MFT sensor will be noisier.

nope. it's because the mft sensor has a smaller full well capacity,
which gives a lower s/n ratio, or more noise.

simple physics.

So you adjust the ISO to the crop factor squared, set it to ISO 200. And then
you adjust your exposure to 1/60, which is four times longer than 1/250.

that's for equivalent images, and actually, it's the f/stop is what
should be adjusted to match depth of field. the shutter speed remains
the same so that motion blur of the subject is the same.

Suddenly, you have given the MFT sensor the same amount of light as the
larger
sensor, and you are thus amplifying the signal comparably. This means that
your
exposure will be next to identical to the larger sensor.

you're once again confusing two different things.

exposure was the same all along. again, handheld light meter.

*if* you want to match noise, *then* you need to adjust iso and f/stop
for an equivalent image.

This, of course, tells us that the "ISO" value is merely a way to achieve a
certain level of brightness, not that the level of amplification is comparable
between the sensors.

more nonsense.

I.e., what I've been saying all along. Nothing has changed.

true, nothing has changed.

you're still confused and refuse to understand why everyone has told
you that.

On 2015-11-24 05:40:15 +0000, nospam said:

In article ,
Sandman wrote:

Sandman:
In fact, I'm the only one that have posted substantiations in
support of my factual statements.

just because you say they're factual does not make it so.

Just because you say they're not doesn't make them disproven.

i and several other people did quite a bit more than just say so.

you haven't offered any proof other than what you created yourself.

that's like asking a bank robber what the facts were.

Sometimes a bank robber will tell you exactly what the facts are, and
you will know what he is saying is true.


--
Regards,

Savageduck

On Tue, 24 Nov 2015 00:40:15 -0500, nospam
wrote:

In article ,
Sandman wrote:

Sandman:
So prove it wrong - merely blowing hot air in my general direction
says exactly nothing.

if anyone is spewing hot air, it would be you.

it's been shown to be wrong multiple times by multiple people.

Message-ID? No? Didn't think so.

if you'd been paying attention, you'd have read the *numerous* posts
where it was explained.

but you haven't. all you're doing is spewing, oblivious to anything
else.

Sandman:
I have proven it correct, using math and example footage. You have
been 100% unable to disprove any substantiation I have supplied,
so they remain valid to this day, regardless of the amount of
whining you do.

you haven't proven anything.

Incorrect. The word "proof" doesn't inherently mean that something is factual
in
itself. It is something that supports a position. I have provided many pieces
of
evidence that support my position.

no you haven't.

you might think you have, but you *definitely* have not.

You have provided exactly none.

yes i did, as did others.

cite a peer-reviewed source that supports your claims or stfu.

Like you did? Hahahahahahaha!!!

you're the one making the claims, so *you* need to back them up.

absent that, you're blowing smoke.

but that much is obvious.

Isn't he a bull****ting b*****d?

He would go to the gallows protesting his innocence of a
mass-slaughter carried out by him in front of thousands.

He is very good at a lot of things, he knows a lot about quite few
things, but he expresses an intolerable ignorance when he is ignorant.

Pity.
--

Regards,

Eric Stevens

On Tue, 24 Nov 2015 00:40:19 -0500, nospam
wrote:

In article , Eric Stevens
wrote:

Sandman:
With a given exposure, a MFT sensors receives
(roughly) one fourth the amount of light as a FF sensor. If
you were to give the MFT sensor the same amount of total
light (I trust you are familiar with how to operate a camera
to give a sensor more light), the signal amplification will
be comparable.

False. Completely false.

So prove it wrong - merely blowing hot air in my general direction says
exactly
nothing.

I've already done so. nospam has done so. Alan Browne has done so.
Whisky Dave has done so. So too have other people whose names I can't
recall at the moment. This is not a topic where you can win by being
stubborn.

no ****.

savageduck, billw, and i think one or two others.

*all* of them have said the same thing, that sandman is wrong.

Floyd too, I think, at one stage.

*Nobody* agrees with him.
--

Regards,

Eric Stevens

On Tue, 24 Nov 2015 00:40:20 -0500, nospam
wrote:

In article , Eric Stevens
wrote:


All my claims have been with equal focal length and f/stop.

Shouldn't you have scaled the focal length according to the crop
factor?

yes, and f/stop too. otherwise it's not equivalent.

Providing he scales the focal length, the f/stop is self-scaling.

yes and no.

people use a lens with an equivalent focal length, but they use the
same f/stop so that the exposure is the same.

for equivalency, the f/stop needs to scale with the focal length so
that the depth of field is the same, but in order to maintain the same
exposure, the iso of the larger sensor needs to be raised.

We are discussing the sensitivity of photosites. Depth of field etc
does not matter, Constancy of illumination does. If you are scaling
down the camera's geometry maintaining a constant f/ number will
maintain a constant exposure.
--

Regards,

Eric Stevens

In article , Eric Stevens wrote:

Sandman:
In order to do this, the troll often snips out the
context in which a statement was made, and attack the
statement on its own, isolated from the context, like you did
in this part of the thread, reference he



Eric Stevens:
Those statements stand on their own.

Sandman:
But have to be taken out of their context to be attacked
semantically by a troll.

Bull****.

Great comeback.

Sandman:
I have, correctly, used the terms as used by people.
This very thread has the subject "How to measure ISO". ISO is
amplification of signal (unless it's the base ISO), and this
is what people refer to as sensor sensitivity. Very much like
you did he

Eric Stevens:
Back to the beginning. You haven't learned or (more likely)
understood a thing.

Sandman:
Such as? Don't be afraid to be specific.

Lots of people have been specific in the past. What's the point of
being specific once again?

So you can't be specific, figures. So now we have two trolls with nothing but
hot air. And you were doing so great for a short while.

Eric Stevens:
What is more you use words in a very loose fashion entirely
unsuitable for the discussion of a technical subject.

Sandman:
This wasn't a technical subject from the start.

That's what you thought, even though you made a technical
pronouncement.

But not on a technical level.

Sandman:
It gradually became more and more technical when nospam couldn't
wrap his head around the facts. Then you joined and you did get
it, your math corroborated my math and it would have been just
nice if you hadn't gone south when you realized you agreed with
me.

nospam has definitely got his head around the facts. It is you who
is away in lala land.

Sorry, Eric. I am the one that have provided support for my claims, you and
nospam are the ones that have not (other than the equations you did that
confirmed my support).

As long as you're one the floor crying, your words mean exactly nothing.

Sandman:
"See
https://photographylife.com/what-is-iso-in-photography "In
very basic terms, ISO is the level of sensitivity of your
camera to available light."" / Eric Stevens- 11/11/2015

Eric Stevens:
True.

Sandman:
"Amplification is NOT sensor sensitivity." / Eric Stevens-
11/21/2015

Funny you should ignore this contradiction and your wiggling.

With a given exposure, a MFT sensors receives
(roughly) one fourth the amount of light as a FF sensor.
If you were to give the MFT sensor the same amount of
total light (I trust you are familiar with how to operate
a camera to give a sensor more light), the signal
amplification will be comparable.

Eric Stevens:
False. Completely false.

Sandman:
So prove it wrong - merely blowing hot air in my general direction
says exactly nothing.

I've already done so.

No, you have not. All you need is to post a message-ID to where you think you
did so. I know you won't, you'll just claim you did and hope no one notices
you're just blowing hot air yet again.

Eric Stevens:
You still haven't understood, have you? Are you talking about
the level of illumination (e.g. Lux) or are you talking about
the total exposure (e.g. Lux x Seconds)?

Sandman:
Both. Pick one.

It's not up to me. You are the one putting up the argument. It's up
to you to tell us what you are talking about.

I have done just that, many times. I don't know how many times you want me to
say the same thing if you didn't understand it the first fifteen times.


--
Sandman

In article , nospam wrote:

Sandman:
So prove it wrong - merely blowing hot air in my
general direction says exactly nothing.

nospam:
if anyone is spewing hot air, it would be you.

it's been shown to be wrong multiple times by multiple people.

Sandman:
Message-ID? No? Didn't think so.

if you'd been paying attention, you'd have read the *numerous* posts
where it was explained.

but you haven't. all you're doing is spewing, oblivious to anything
else.

Thanks for proving me correct, you have nothing. Never had anything, and probably
will never have anything. All you have is empty claims and hot air - as always.

Sandman:
I have proven it correct, using math and example
footage. You have been 100% unable to disprove any
substantiation I have supplied, so they remain valid to this
day, regardless of the amount of whining you do.

nospam:
you haven't proven anything.

Sandman:
Incorrect. The word "proof" doesn't inherently mean that something
is factual in itself. It is something that supports a position. I
have provided many pieces of evidence that support my position.

no you haven't.

you might think you have, but you *definitely* have not.

More empty claims from nospam.

Sandman:
You have provided exactly none.

yes i did, as did others.

Keep telling yourself that, hot air boy.

nospam:
cite a peer-reviewed source that supports your claims or stfu.

Sandman:
Like you did? Hahahahahahaha!!!

you're the one making the claims, so *you* need to back them up.

Which I have - and you have countered with exactly zero support.

absent that, you're blowing smoke.

but that much is obvious.

Projection, a common tool for the low-life troll.

--
Sandman