digital camera as exposure meter

(Floyd L. Davidson) wrote:

Another area where a
similar total paradigm shift took place

Paradigm Shift = a preface to braking wind

"Floyd L. Davidson" wrote:

Is the kid in the forground shadows
the subject, or is the house in full sun across the street the subject?

Well, that's where there it clearly *does* make a
difference what type of circuitry is used. The simple
(analog) form for matrix metering simply cannot
distinquish between the two, at all.

You've missed the point. Same camera, same camera position, two different
photographers. One wants a picture of the kid, one wants a picture of the
house. A matrix system that can differentiate the two cases will always be
wrong for one of those photographers.

The photographer has to decide which is the subject and set the exposure
accordingly. The camera doesn't know, and will be wrong some percentage of
the time.

And there's no way to tell the camera which you want.

Rest assured that a digital camera using a CPU to access
a table of 40,000 different patterns is in fact going to
reliably detect that difference.

And be unable to read the photographer's mind. And will guess wrong.

That's why it's such a bad idea for medium format photography.

The problem is that for our example of using the camera
for precision exposure, the camera knows but does not
tell us what it knows. That *can* be worked around, but
it requires apparently more dedication to understanding
technology and attention to detail that some people are
willing to make use of. (And *I* am one of those
people. The calibration required simply is not worth
the effort it takes for my purposes.)

It's not "calibration", it's second guessing what is claimed to be a rather
arbitrary algorithm. (I suspect that real matrix meters are a lot closer to
center weighted metering than any of the mfrs would like to admit to,
though.)

And since it's an algorithm, the complexity of second guessing it truly
nasty.

Do
you need shadow detail for the kid, or do you need to hold the highlights
at
the expense of shadow detail? You don't know what the matrix meter will
decide. And it'll change its mind with slight changes in composition, so
checking the histogram, dialing in an exposure compensation, and
reshooting
won't necessarily work if you change the composition even slightly (note
that this is true for centerweighted metering as well).

Basically, matrix metering is for incompetent photographers on the hope
that

Oh, another one of these people who figures that anyone
not using their methods to create exactly the same
results they do, is incompetent by definition.

I'm perfectly open to new means of measurement that will _reliably_
determine exposure.

Matrix metering doesn't meet that requirement. It's a shortcut when you
don't have time to actually measure the light.

*WRONG*.

Some people have different needs, different styles, and
want to produce different results. There *are*
competent photographers who make good use of matrix
metering.

If you care that a particular single exposure is correct, you can't use
matrix metering for it. You have to decide what you want and make the
measurements required to determine the exposure. Matrix metering is only
interesting if you are happy with some percentage of your shots being wrong.

This thread is about a meter for use with MF film. MF film users like to
make every frame count. So we need a metering method that is reliable. Not
one that randomly picks "one of 40,000 patterns".

it'll up the percentage of good guesses. Incident and spotmetering
actually
measure the light and give you meaningful measurements that you can use to
determine good exposures.

Incident metering is not significantly better than
averaging with a reflective meter. It's just one big
guess, rather than two big guesses...

It sounds as though you don't understand incident metering: Incident
metering measures the light and produces a technically correct exposure for
reflective subjects. I personally don't find it particularly useful for my
photography, but it is _accurate_, _reliable_, and _repeatable_. All the
things that matrix metering isn't.

meter with a gray card. But a simple spot meter is lighter and easier to
use.

Perhaps, perhaps not.

The Pentax digital spot meter is a joy to use, being one of the most
brilliant examples of KISS engineering ever: it has all of one button. Aim,
push, read an EV value, plug into zone scale. Done. And it's lighter than
any dSLR. With the more bells-and-whistles rich meters, you'll need to RTFM
to figure out how to get a simple reading. But they're still lighter and
more compact than a dSLR.

David J. Littleboy
Tokyo, Japan

Lobby Dosser wrote:
(Floyd L. Davidson) wrote:

Another area where a
similar total paradigm shift took place

Paradigm Shift = a preface to braking wind

For Luddites, that is probably true.

Lots of them became unemployed too...

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

Floyd L. Davidson wrote:

snipped

Floyd, you have a scary level of blind faith in high technology.

Lobby Dosser wrote:
Noons wrote:

Total nonsense. A histogram and a "blink-on-over-exposure"
are not a result of the metering function itself!

Not only that, but the histogram is available in Many point and shoot
digitals. DSLR not needed. The guts are the same for the same resolution.

I sometimes use a G7 as a meter for some of my vintage kit when I haven't got
a meter to hand, but the range isn't ideal as typical "P&S" cameras do not
have the range of apertures usually. Often they stop down to F/8 or if you're
lucky F/11. With such a small sensor they have no need of F/22 or F/32.

Floyd L. Davidson wrote:
Noons wrote:
Care to specify exactly what is that "magic
wand" "advanced technology"? Or do you expect
the rabble to just gawk in awe at the statement?

Start with reading and understanding the significance of
"A Mathematical Theory of Communication" published in
1949 by Claude Shannon. That is the basis of
_Information Theory_, which is what has defined the
leading edge of data technology for nearly 6 decades.

And it is the theory behind imaging technology today.
The digital photography technology involved is mixed
between communications and computational.

Sorry, remind me: what has this got to do with metering?


If you want an example that demonstrates what is
currently happening with imaging, and the extent to
which it will extend, just take a look at the history of
telecommunications, where the initial thrust of
Shannon's work was directed. Another area where a
similar total paradigm shift took place (except it
wasn't on such a massive scale and it happened over a
very short period of time) was the newspaper publishing
industry.

That's nice. Anyway, this guy is using MF film.


From the advent of digital cameras costing $50,000 to
having them built into every cell phone just because
it's a cheap bauble, digital technology is
revolutionizing the nature of photography, and it has
just barely started.

Jolly good. So, why is a DSLR a better meter than a meter?


Saying it isn't better just because it is digital is
an indication that someone does not understand what
is in fact taking place, or why. It *is* better, and
the specific reason is indeed because it is digital.

I said it is not better because it is digital. Meaning just because it is
digital does not make it better, not because it is digital, it is not better.

I thought it was clear, but...


Nobody is denying that a T90, or other film camera,
would work. Just that a digital system would be
even nicer.
No it would not. It won't measure light
appropiately for film use.

It will. (The idea that it can't is a bit hilarious
too, but it does hint at just why you argue what you
do.)

Even if it does, it is still more expensive, heavier and bulkier than a meter
which will be at least as good, possibly better, and therefore not as good
overall.


I didn't say it was a T90.

Actually, you did. In fact, it makes no difference
which camera it is, the T90 is just an example (of
*your* choice, not mine). Interesting that you use it
as your example, and then complain that I do too.

I think it was me that suggested a T90. Really nice meter in those. Far too
big and heavy to carry out unless you're also using it as the camera, but very
accurate meter.


Is that due to some lacking in the digital cameras, or
your inability (or unwillingness) to understand how to
be functional with the technology? ;-)

So you suggest the OP gets a DSLR instead of a meter and then compensates for
the deficiencies instead of getting a meter for half the price?

Floyd L. Davidson wrote:
Lobby Dosser wrote:
(Floyd L. Davidson) wrote:

Another area where a
similar total paradigm shift took place
Paradigm Shift = a preface to braking wind

For Luddites, that is probably true.

Lots of them became unemployed too...


So somebody who decides to buy a fancy light meter instead of an expensive
DSLR to use as a meter is a Luddite?

Interesting point of view. Discussions with you are *fascinating*, Floyd.

Paul Mitchum wrote:
Neil Gould wrote:

Recently, Paul Mitchum posted:

Floyd L. Davidson wrote:

Richard Polhill wrote:
[..]
But a good (£300) meter is a lot cheaper than a digital camera and
24-200 lens.
A $600 camera (Nikon D40 with an 18-55mm kit lense) will run circles
around any $600 light meter. [..]
Can I hook my strobes to it for metering purposes?
One should be able to hook strobes to a digital camera or a photo meter
(with flash capabilities). The issues remain the same, the digital camera
records the light from the strobes calibrated to the sensor, the meter
records the same light calibrated to film. Chances are very good that the
two methods will not give equivalent exposure data under that usage.

You've never used strobes, have you? You *need* a strobe meter if you
want to meter the strobes. If you want to guess and shoot and 'meter'
against the histogram, then, well, you could do that, too, but don't
look for work at an ad agency or anything.


Paul, I think you've got the wrong guy.

Niccolo Machiavelli wrote:
In article ,
(Paul Mitchum) wrote:

Richard Polhill wrote:
[..]
But a good (£300) meter is a lot cheaper than a digital camera and
24-200 lens.
A $600 camera (Nikon D40 with an 18-55mm kit lense) will run circles
around any $600 light meter. [..]
Can I hook my strobes to it for metering purposes?

Different needs require different equipment.

In article ,
"Neil Gould" wrote:

It's pretty clear that you didn't understand what I wrote, above. FWIW,
I've owned and used strobes for well over 30 years, now. When shooting
film, I do use a flash meter, so what's your point?

You *need* a strobe meter if you
want to meter the strobes.

If you read my other posts in this topic, I wrote that using a digital
camera as a meter for shooting film is not terribly useful. That really
has little or nothing to do with strobes, because as I wrote above,
"...the issues remain the same".

Please make up your mind Mr. Gould. The OP was looking for
recommendations on using a digital camera as a light meter for his
medium format equipment. you said, among other things, "A $600 camera
(Nikon D40 with an 18-55mm kit lense [sic]) will run circles around any
$600 light meter."

No, that was Floyd.


But now that is not the case any more, as "I wrote that using a digital
camera as a meter for shooting film is not terribly useful."

Except for studio strobes -- remember you did say _any_ light meter:
"I've owned and used strobes for well over 30 years, now. When shooting
film, I do use a flash meter, so what's your point?"

Well, the point is if a Nikon D40 can run rings around a dedicated flash
meter why are you using such a useless and obsolete thing?

You're confusing posters, mate.


I suppose the point is, too, that you have burned up a considerable
amount of bandwidth trotting out arguments on the innate superiority of
digital cameras for every and all applications, even for the laughable
use as a flash meter (except when _you_ use one, of course) without once
recognizing that different tools are meant for different purposes.

You of course are free to use what you want and to advocate what you
use. However, you might find that most people don't agree with you -- or
with each other.

Tell me, if you would, which has the "correct" grain pattern, Tri-X or
HP-5, both in rollfilm format? The same films in 8" x 10"? I've always
wanted to know if I am shooting the correct film. Perhaps I should use a
DSLR instead? After all, film is dead and you can use a DSLR as an
incident light meter. And can you recommend which DSLR to use to get the
range of movements of my Deardorff 8" x 10"?

--Nicco

If you talk to Floyd, he'll tell you how superior advanced technology makes
movements obsolete or something. ;-)

Floyd L. Davidson wrote:

There are $800 DSLR's that come with a lense, of course.


Sorry, I can't take a man seriously when he talks about photography without
being able to spell lens.