rehess Loc: South Bend, Indiana, USA

Some are artists, some not so much. Valuing "Weegee" Fellig or Nick Ut, or the dad down the block has nothing to do with valuing artists.

Bipod

If only it were that simple....

If your daughter underrstands all about magnetic storage media, hardware, device
driver sofrtware, file formats and compression algoritihms, and the standards and
patents controlling it all, then what the heck is she doing working for peanuts in a
library?

The Library of Congress selected the wrong device for audio recordings--it's no
longer made. So now the US taaxpayer has to foot the bill for custom manufactured
tape recordets costing tens of thousands of dollars each. Most of us aren't lucky
enough to have a rich Uncle.

You can get a audio tape recorder custom made---for a price--because they are extremely
simple. But try gettting someone to build you a Betamax! Or a Zip drive! All the
King's horses and all the King's men couldn't do it. The required ASIC chips are no
longer made--and all the project deisgn documentation was probalby lost agees ago.

Each media has it's litttle peculiarities. Tape needs to be respooled periodically
or it bleeds through. Not a problem in ciruclating libraries---big problem in archives.

You can't read the media without a reader. Can't use the reader without a
compatible IO interface--plus device drivers fro the interface and for the reader.
You can't use the device driver without the right OS version and any required
service packs, etc. And you can't install the the OS except on a compatible
platform.....

And so it goes....a long list of hardware and software that must be the correct
version to work. None of it is under your control, nor can you or your daughter
be expected to understand how it works or how the computer industry works
(or often, doesn't work and leaves users high and dry).

If you plan on transferring from media to media and format to format for years
and decades, you only have to guess wrong (or blow it) once.

What is the oldest digital data in your possesssion? I'm guessing it's newer than
your oldest kitchen appliance, wrist watch, or even dress shirt.

But I've got B&W prints in the family albums from before the US Civil War that
look great. The reason they've survived is that nobody messes with them.

rehess Loc: South Bend, Indiana, USA

All she has to understand is to periodically copy the JPEGs to currently modern devices. "Bleed through" is not an issue with digital files. You may panic all you want. Hysteria gets boring rather fast.

[unwatch]

Bipod

Man, you got a lot to learn about digital electronics--and conservation
of materials.

Like um, about the lack of real standards.
And creeping file format changes.
And compression algorithms that go away for patent reasons.
And CDRs containing cyanine dye that suddenly become unreadable.

Even "modern" media are physical---and your data isn't carved in stone.
(If it was, it could last for 4,0000 years like the Pyramid texts. Because
stone is inert and can always be read.)

But alas, you data is just a magnetic domain, or a dot in a dye layer,
or the state of a semiconductor.

Let's get specific: how old is your oldest document in your possession?
Mine is page of illumanted manuscript on vellum.

How old is the oldest photo in your care?

If you don't care about conservation--that's fine, just say so.

Tomcat5133 Loc: Gladwyne PA

Wallen I chose quote reply to say: If you have a camera with good ISO and I have the Sony FF a7s II
which is amazing at low light it opens the door to so many different situations. Here are some examples:
1. The first one is in a very dim dinner room. I shot stills and made a PR video for them. 3. Lady Tennis was very dark in corner trade show. 3. A cousin in a dark room with only natural light. 4; Test in chinese restuarant dark day dim restuarant. I will say I used the first a7s for these. And a great lens Sony 55mm
1.8 zeiss lens. As you can see the lens make some difference. I hope this inspires you.
I have flashes dont use them very often. Go for it and have fun.

(Download)




(Download)

Wallen Loc: Middle Earth

It seems many readers fail to see the gist of the question. Many argue of just shooting it whatever the consequence while some speak of their very good & capable equipment. It is not about missing a shot or specific equipment/set-up. The question is about a standard to which we can actually compare capabilities.

As an example, we start with a value of 100lux and we shoot a test panel at 2 meters with a lens of t-stop value 2. Let us assume this value as ISO 100. Then we lessen the lux by 10 and shoot again. At what point (lux) will the test camera have 50% noise compared to the clean image. Then that should be the standard rated optimal limit. Beyond that point would be called extended ISO.

Then other cameras will be set up the same and their output rated as per the standard done above. Hence if all cameras will be tested and rated this way, all ISO values stated in cameras will all be comparable.

The main thing here is that ISO is supposed to be a standard. The truth is it is not. every manufacturer goes their own way. If it is a standard being followed, all cameras will have the same image quality when compared at any ISO setting-within their optimal limit as they are rated to their "ACTUAL WORKING ISO".

Wallen Loc: Middle Earth

In layman's language & technology level aside, why would a D500 ISO12800 looks better than a D7000 ISO 12800? Because they are are not following a standard.

Something like this:

D500 ISO 1600 = D7000 ISO 3200
D500 ISO 3200 = D7000 ISO 6400
D500 ISO 6400 = D7000 ISO 12800
D500 ISO 12800 = D7000 ISO Hi
D500 ISO 25600 = (nil)
D500 ISO 51200 = (nil)

If given an actual working ISO, it will be something like this:

D500 ISO 50(native) = D7000 ISO Low
D500 ISO 100 = D7000 ISO 100(native)
D500 ISO 1600 = D7000 ISO 1600
D500 ISO 3200 = D7000 ISO 3200 (limit)
D500 ISO 6400 = D7000 ISO 6400(boosted)
D500 ISO 12800(limit) = D7000 ISO 12800(boosted)
D500 ISO 25600(boosted)= D7000 ISO Hi (max boost)
D500 ISO 51200(boosted)= D7000 (nil)

If it is standard then we can directly compare the ISO capability of the camera.

splatbass Loc: Honolulu

There is a time and place for high ISO. For landscapes I try to use the lowest possible ISO, but I also like to shoot night street photography. For that I have my D750 set to max 12,800 ISO. I have perfectly acceptable pics at 12,800. Of course a certain amount of noise is acceptable in street photography.

Bipod

Film speed isn't a physical quantity derived from science, like velocity, mass, or temperature.
It has connections with two engineering concepts: sensitivity and gain. But it's really just a
convenience number, like shoe size or dress size. If you were a size 10 shoe, the question
"10 what?" has no answer.

Obviously the inside of a shoe is an irregular shape, and it would take a lot of measurements
to adequately describe it. But we need one number (sometimes augmented by a width).


"ISO 100" seems so real, it's hard to remember that the term has no meaning except
with respect to some particular standard, which sets forth the method used to measure it
and how the number is dervived from the test data. And we forget that ISO is actually
an acronym for a standards organization.

The definition of "ISO 100" for film and digital are so different, that they are basically
two completely different measures. For film, it is baesd on the Characteristic Curve
(also called Hurter-Driffield Curve: negative density plotted against log of exposure,
all this assuming some "standard" development). But for digital, there is no negative,
no density and no development.

In both film and digital, speed atttempts to reduce a empirically dervived curve to a single
number. Obviously, this is somewhat arbitrary. Moreover, the standards have changed many
times over the years, and so have the standardsd bodies:
ASA -- American Standards Association (later renamed ANSI),
NAPM --- National Association of Photographic Manufacuters
ISO -- International Standards Organization

B&W Negative film:
US:
1943 ASA Z38.2.1
1946 -- revised
1947 -- revised
1954 -- superseded by ASA PH2.5-1954
1960 -- superseded by ASA PH2.5-1960
1979 -- revised
1986 -- adopated in the US as NAPM IT2.5-1986
1993 -- revised
International:
1974 ISO 6-1974
Both:
1993 ISO 6-1993

Before 2006, there was no speed standard for digital cameras: manufactuers each came
up with it's own way of arriving at "ISO" numbers (which had nothing to do with the
International Standards Organization).

Then came ISO 12232:2006 "Photography -- Digital still cameras -- Determination of exposure
index, ISO speed ratings, standard output sensitivity, and recommended exposure index"
This was superseded by ISO 12232:2019 -- the current standard.

Unfortunately, the text of ISO standards have to be purchased and are quite expensive.
So I have to rely on secondary sources.

According to Wikipedia:
"The ISO standard ISO 12232:2006[63] gives digital still camera manufacturers a choice of five different
techniques for determining the exposure index rating at each sensitivity setting provided by a particular
camera model. [ . . . ] Depending on the technique selected, the exposure index rating can depend on the
sensor sensitivity, the sensor noise, and the appearance of the resulting image. The standard specifies the
measurement of light sensitivity of the entire digital camera system and not of individual components such
as digital sensors, although Kodak has reported[65] using a variation to characterize the sensitivity of two
of their sensors in 2001. "

So ISO 12232:2006 is a good example of a "non-standardizing standard": the standard just codifies
the lack of standardization. (Something similar was done in the ANSI standard for light meter
calibration--which is why light meters from different manufactuer's can give different readings,
even when correctly calibrated.)

In fact, manfacturers generally don't want it to be easy to compare their cameras with those of
their compeitor, or to test advertising claims.

Worse, there is no way to know whether a particular manufacture is or isn't following the standard
the standard on a particular camera, since compliance is voluntary, and there is no independent
laboratory testing of cameras.

Finally, there are two engineering notions that may be relevant:

Generally in electronics, sensitivity is defined as the smallest amplitude input that will produce
a measurable output. With a camera we are not just concerned with very weak signals, but with
the entire range of luminances that may be in the frame.

Noise is generally expressed as a signal-to-noise ratio. For a camera, the basic idea is that a given
pixel represents eithe signal (the image) or noise. Exactly how to figure it is another question.

Wallen Loc: Middle Earth

-Film speed is based on reactive properties of a chemical which is affected by grain size which is not part of the question at hand.

-ISO as you have said is a standardization body but for our purpose is related to Gain & Sensitivity, both properties can be measured precisely but are being mis-represented by the manufacturers.

-Sensor pixels generally deal only with luminescence which are filtered to represent color.

-In electronics be digital or analog, signal to noise ratio is easy to figure out. Designing amplifiers that produce clean signals are the tricky bit and that is also beyond the scope of the thread.

Summarily, we both just agreed that manufacturers do not want us consumers to know the facts and are twisting details to benefit themselves.

Tomcat5133 Loc: Gladwyne PA

My Sony a7s (which I sold) and got the a7s II which is an amazing camera. It is a low light master.
Is can shoot in very low light. And the images are very good.

That said camera's have to be checked or researched in many dont perform as the ISO's
they claim. ISO 1600 sounds good. Test in increments in your living room.
I take my cameras and shoot in the house in dim light to see what they really do.