"scientific" vs "geometric" shutter speed designations

[DWThomas]

Looking at EXIF data from iPhone photos adds some fun -- stuff like 1/2959 at f/2.2, 1/2653 @ f/2.2, 1/437 @ f/2.2 -- it appears to do micro adjustments of shutter speed using aperture priority for a sizable (no doubt maximum) aperture.

 

[BrianShaw]

Now that’s what we want... truly accurate exposure data!

 

[David Lyga]

Okay... I’ll play. After a 10-hour workday I’m feisty!

A light meter measures light in scientific terms - lumen or lux or candelas - not a “LV”. The presence of an exposure calculator (or direct exposure readout) makes the photographic meter, indeed, an exposure meter.

Shutter time vs shutter speed is classic mental masturbation...

There are some things that are really wrong, like calling a tomato a vegetable instead of a fruit. But then there are some things not worth making more precise, like hoagie vs submarine. Now “grinder”... THAT’S something totally different.

In Connecticut, where I grew up, it is always 'grinder'. To me, this sounds far less obscene than Philadelphia's 'hoagie' or New York's 'hero'.

But, Brian, either way, such discursive bantering is not wrong and becomes a level of preference. To me, 'light meter' simply makes more sense. To you, the opposite. I am not going to call you on this 'correction'; nor am I going to conform to your way of thinking. Either way, we understand each other. "Intendiamoci" as my Italian half says.

LV refers to the Latin lux, lumen, or candelas. So, it is not 'wrong' unless you are being tested for Latin. There are conformance guidelines but we all know what one is saying.

After a ten hour shift you are tired; and since it is past my 8 PM bedtime, I also am tired. It is tempting to continue but my feeble brain is being taxed. - David Lyga

 

[Sirius Glass]

there are several speed ranges:

the old one:
1 - 2 - 5 -10 - 25 - 50 - 100 -200 - 400

the current one
1 – 2 – 4 – 8 – 15 – 30 – 60 – 125 – 250 – 500 – 1000 – 2000 – 4000

the correct one
1 – 2 – 4 – 8 – 16 – 32 – 64 – 128 – 256 – 512 – 1024 – 2048 – 4096

The issue with the common, actually applied versions (late and current) is just that they are intended to avoid crooked mumbers. That is all. No idea what "scientific" has to to with that.


I rather wonder that those numbers are reason for discussion, but not the terminlogy "shutter speed", when actually times or more correct time-periods are given (by means of nominator of a fraction).

1 – 2 – 4 – 8 – 16 – 32 – 64 – 128 – 256 – 512 – 1024 – 2048 – 4096 is not connect. We are working with film which is not digital, rather analog. I use ISO 400 speed film not 512.

 

[David Lyga]

1 – 2 – 4 – 8 – 16 – 32 – 64 – 128 – 256 – 512 – 1024 – 2048 – 4096 is not connect. We are working with film which is not digital, rather analog. I use ISO 400 speed film not 512.

I am confused here: "512" refers to a shutter speed (time), not a film speed index.

EDIT: Sorry, you DID mean film speed. OK, so what? The geometric theory here does not neatly conform with the easier to read and digest '400'. But the range is still correct, in that '512' is faster than '400. - David Lyga

 

[Sirius Glass]

I am confused here: "512" refers to a shutter speed (time), not a film speed index.

EDIT: Sorry, you DID mean film speed. OK, so what? The geometric theory here does not neatly conform with the easier to read and digest '400'. But the range is still correct, in that '512' is faster than '400. - David Lyga

1/ISO is the shutter speed that Sunny 16 starts with. Also the rule of thumb that the 1/focal length is the slowest speed for hand holding. I do not see many lenses with focal lengths of 32mm, 64mm, 128mm, 256mm, 512mm, 1024mm, ...

 

[AgX]

Shutter time vs shutter speed is classic mental masturbation....

Not for someone constantly switching between languages. Then this or even more something as shutter-priority AE versus aperture AE are each time a kind of stepping stone, making one pause, thinking whether one got it right. At least that is my experience.

 

[RalphLambrecht]

I’ve never heard that terminology distinction of “scientific “ Vs “geometric “. Is that something Rockwell concocted or is it common lingo that is just new to me? I use shutters with both (different shutters, of course) and always thought of it as older and newer sped progressions. But beyond that I never really worried about the difference or really wondered.

It is something Rockwell concocted; it's the difference between linear or geometric timing and both are designed to double or half the exposure just like a step in aperture change does.

 

[AgX]

It is something Rockwell concocted; it's the difference between linear or geometric timing and both are designed to double or half the exposure just like a step in aperture change does.

All ranges shown in this thread are linear (arithmetic), not geometric.
So I have no idea what Rockwell is talking about.

 

[miha]

Not for someone constantly switching between languages. Then this or even more something as shutter-priority AE versus aperture AE are each time a kind of stepping stone, making one pause, thinking whether one got it right. At least that is my experience.

Same here. And I don't get "lens speed" either. In may language (as well as in German?) it's "brightness strength" to characterize relative aperture of a lens.

 

[JPD]

I am old (REALLY OLD) enough to have witnessed cameras whose shutter speed designations were routinely stated non-geometrically. What I never could understand was WHY it was somehow 'better' to state shutter speeds in that way, since transferring data, via EV values, would then be very difficult.

It was the F. Deckel company who developed the EV concept in the 1950's. It was at that time the set of shutter speeds changed (to 1/15, 1/30, 1/60 and so on) and the aperture settings changed to even space between the settings, so coupling the Compur shutter to the EV system became possible. It also made it easier to couple the shutter speed and aperture settings to the light meter. It was one of those improvements that happened over time.

 

[RalphLambrecht]

Now that’s what we want... truly accurate exposure data!

god bye: data analysis and welcome : data paralysis!

 

[David Lyga]

god bye: data analysis and welcome : data paralysis!

I do wish that I could understand what is so restrictive about geometrical analysis. I see no straitjackets at work here. - David Lyga

 

[Chan Tran]

The Nikon F3 which was introduced 40 years ago has the standard shutter speed listed in the service manual as following
1/1000 0.976mS
1/500 1.95mS
1/250 3.91mS
1/125 7.81mS
1/60 15.6mS
1/30 31.2mS
1/15 62.5mS
1/8 125mS
1/4 250mS
1/2 500mS
Which correspond to 1024, 512, 256, 128, 64, 32, 16, 8, 4, 2 etc..

 

[David Lyga]

The Nikon F3 which was introduced 40 years ago has the standard shutter speed listed in the service manual as following
1/1000 0.976mS
1/500 1.95mS
1/250 3.91mS
1/125 7.81mS
1/60 15.6mS
1/30 31.2mS
1/15 62.5mS
1/8 125mS
1/4 250mS
1/2 500mS
Which correspond to 1024, 512, 256, 128, 64, 32, 16, 8, 4, 2 etc..

And that intellect on the part of a prescient Nikon pleases David Lyga. Why? Because the progression is geometric, allowing for easy EV transfer.

The older 'scientific' progression does NOT aid with this translation because one number does not double (or halve) the next.

When you have: 1, 2, 5, 10, 25,, 50, 100, 300 .... you increase too fast and this is not mere 'rounding error; but, rather, a skewed presentation which is not easily transferable with regard to EVs. When a combined EV value is known, as 'EV 15' for T MAX 100 under sunlight, you KNOW how to change the shutter speed and aperture value. You are not 'restricted' to the sunny f16 rule because you now don't have to use only f16. - David Lyga

 

[DonW]

I love this stuff! Thanks David!

 

[David Lyga]

I love this stuff! Thanks David!

Just tell me to shut up when you have had enough. - David Lyga

 

[BrianShaw]

Not for someone constantly switching between languages. Then this or even more something as shutter-priority AE versus aperture AE are each time a kind of stepping stone, making one pause, thinking whether one got it right. At least that is my experience.

I get confused by the use of the term “G-cramp” in British English and “C-clamp” in American English for the same tool. But it’s just not that difficult to understand synonyms. Determining which one is proper and correct might initiate another revolution!

 

[Sirius Glass]

All ranges shown in this thread are linear (arithmetic), not geometric.
So I have no idea what Rockwell is talking about.

Neither does Rockwell. Never has and never will.

 

[Alan Edward Klein]

Okay... I’ll play. After a 10-hour workday I’m feisty!

A light meter measures light in scientific terms - lumen or lux or candelas - not a “LV”. The presence of an exposure calculator (or direct exposure readout) makes the photographic meter, indeed, an exposure meter.

Shutter time vs shutter speed is classic mental masturbation...

There are some things that are really wrong, like calling a tomato a vegetable instead of a fruit. But then there are some things not worth making more precise, like hoagie vs submarine. Now “grinder”... THAT’S something totally different.

Hero!

 

[Sirius Glass]

Not for someone constantly switching between languages. Then this or even more something as shutter-priority AE versus aperture AE are each time a kind of stepping stone, making one pause, thinking whether one got it right. At least that is my experience.

I get confused by the use of the term “G-cramp” in British English and “C-clamp” in American English for the same tool. But it’s just not that difficult to understand synonyms. Determining which one is proper and correct might initiate another revolution!

We are separated by a common language.

From My Fair Lady:

Henry Higgins: Look at her, a prisoner of the gutter,
Condemned by every syllable she utters
By right she should be taken out and hung,
For the cold-blooded murder of the English tongue.
Eliza Doolittle: Aaoooww!

Henry (imitating her): Aaoooww!
Heavens! What a sound!
This is what the British population,
Calls an elementary education.

Pickering: Oh Come sir, I think you picked a poor example.

Henry: Did I?
Hear them down in Soho Square,
Dropping "h's" everywhere.
Speaking English anyway they like.
You sir, did you go to school?

Man: Wadaya tike me for, a fool?

Henry: No one taught him 'take' instead of 'tike!
Hear a Yorkshireman, or worse, hear a Cornishman converse. I'd rather hear a choir singing flat.
Chickens, cackling in a barn, just like this one (pointing to Eliza)

Eliza: Gaaarn

Henry (writing, imitating Eliza): Gaaarn..
I ask you Sir, what sort of word is that? (to Pickering)
It's "aoow" and "gaarn" that keep her in her place
Not her wretched clothes and dirty face
Why can't the English teach their children how to speak?
This verbal class distinction, by now,
Should be antique. If you spoke as she does, sir,
Instead of the way you do,
Why, you might be selling flowers, too!

Pickering: I beg your pardon!

Henry: An Englishman's way of speaking absolutely classifies him,
The moment he talks he makes some other
Englishman despise him.
One common language I'm afraid we'll never get.
Oh, why can't the English learn to
set a good example to people whose
English is painful to your ears?
The Scotch and the Irish leave you close to tears.
There even are places where English completely disappears.
Well, in America, they haven't used it for years!​

 

[Vaughn]

...When you have: 1, 2, 5, 10, 25,, 50, 100, 300 .... you increase too fast and this is not mere 'rounding error; but, rather, a skewed presentation which is not easily transferable with regard to EVs...- David Lyga

My Graphic22 and Ciro-flex have Wolli shutters that go 10-25-50-100-200
And a Rollieflex at 1-2-5-10-25-50-100-250

All close enough to one stop apart to make little difference to me, since my metering system is different (figure out the exposure needs, pick a suitable aperture/shutter speed combo for the image, and set the shutter as close as possible. With the Rollei, if I have fast film and plenty of light, I might take advantage of the slightly bigger jump in shutter speed that going from 1/100 to 1/250 can give me (might be 1/200 anyway with these old workhorses).

 

[David Lyga]

My Graphic22 and Ciro-flex have Wolli shutters that go 10-25-50-100-200
And a Rollieflex at 1-2-5-10-25-50-100-250

All close enough to one stop apart to make little difference to me, since my metering system is different (figure out the exposure needs, pick a suitable aperture/shutter speed combo for the image, and set the shutter as close as possible. With the Rollei, if I have fast film and plenty of light, I might take advantage of the slightly bigger jump in shutter speed that going from 1/100 to 1/250 can give me (might be 1/200 anyway with these old workhorses).

Little jump plus little jump adds up. Your end figure for the Rolleiflex should, theoretically be "125" which is quite different from "250", a full step off. Hence: 1, 2, 4, 8, 15, 30, 60, 125 - David Lyga

 

[BrianShaw]

One can always adjust the aperture to get a “half-step”, etc if that’s what’s needed. Little jump back.

 

[AgX]

In the times of changeover Gossen introduced in 1952 a meter that even showed old and new range:

https://de.wikipedia.org/wiki/Blendenreihe_(Optik)#/media/Datei:Skala_Gossen_Sixtomat_1952.jpg