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Meaning of ISO value in digital photography?



 
 
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  #41  
Old June 20th 18, 01:31 PM posted to rec.photo.digital
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Posts: 24,165
Default Meaning of ISO value in digital photography?

In article ,
Sandman wrote:

In film cameras, ISO referrs to the sensitivity to light of the
emulsion. Manufacturers formulate different film emulsions with
different sensitivites tarding increased grain with increased ISO
speed.


In a digital camera, presumably the sensor does not adjust itself to
have greater sensitivity. Or does it?


So what is happening in a digital camera when I choose a greater ISO
setting? Is more amplification being used?


Short answer: yup.


correct.

ISO for film and "ISO" for digital sensor has very little in common.


not correct.
  #42  
Old June 20th 18, 01:31 PM posted to rec.photo.digital
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Posts: 24,165
Default Meaning of ISO value in digital photography?

In article , Carlos E.R.
wrote:


In film cameras, ISO referrs to the sensitivity to light of the
emulsion. Manufacturers formulate different film emulsions with
different sensitivites tarding increased grain with increased ISO
speed.

In a digital camera, presumably the sensor does not adjust itself to
have greater sensitivity. Or does it?

So what is happening in a digital camera when I choose a greater ISO
setting? Is more amplification being used?

Short answer: yup.

ISO for film and "ISO" for digital sensor has very little in common.


I thought they had quite a lot in common as it stands for International
Standards Organization which covers light sensitivity of a sensor or film
doesn't matter which.

That's what it means by a standard, previously film was ASA which was
american while Europe used DIN , so a new standard was created for everyone
with digital or film and it was called ISO not to be confused with ios of
course.


I would think that a film camera loaded with film of a certain iso
rating and a digital camera adjusted to that same iso rating do a
similarly lighted photo when adjusted to the same diaphragm and shutter
speed, so that a photographer can adjust both with the same settings
using the same handheld light measurement instrument.


that is correct.
  #43  
Old June 20th 18, 03:24 PM posted to rec.photo.digital
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Posts: 24,165
Default Meaning of ISO value in digital photography?

In article ,
Whisky-dave wrote:


I would think that a film camera loaded with film of a certain iso
rating and a digital camera adjusted to that same iso rating do a
similarly lighted photo when adjusted to the same diaphragm and shutter
speed, so that a photographer can adjust both with the same settings
using the same handheld light measurement instrument.


That is the general idea similar to any standard.

Previously germany and some of europe had the DIN standad for film speeds in
the 1930s. DIN 18 was 50 ASA or 50 ISO.
They may have tweeted the figures a little like they do with the speed of
light can be quoted as 186,000 miles per second or 300,000 km/s

but a mile is 1.60934 km so 1.60934X186,000 = 299,337.24 km/s

So which is corect for most of us it doesn't matter.


math fail.
  #44  
Old June 20th 18, 03:48 PM posted to rec.photo.digital
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Posts: 24,165
Default Meaning of ISO value in digital photography?

In article ,
Whisky-dave wrote:


Previously germany and some of europe had the DIN standad for film speeds
in the 1930s. DIN 18 was 50 ASA or 50 ISO.
They may have tweeted the figures a little like they do with the speed of
light can be quoted as 186,000 miles per second or 300,000 km/s

but a mile is 1.60934 km so 1.60934X186,000 = 299,337.24 km/s

So which is corect for most of us it doesn't matter.


math fail.


But I converted it from c= 1 foot per nanosecond the new SI unit. ;-P


whoosh.
  #45  
Old June 20th 18, 04:24 PM posted to rec.photo.digital
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Posts: 24,165
Default Meaning of ISO value in digital photography?

In article ,
Whisky-dave wrote:

speed of
light can be quoted as 186,000 miles per second or 300,000 km/s

but a mile is 1.60934 km so 1.60934X186,000 = 299,337.24 km/s

So which is corect for most of us it doesn't matter.

math fail.

But I converted it from c= 1 foot per nanosecond the new SI unit. ;-P


whoosh.


So why don't you explain this maths fail what is the speed of light in your world ?


sig figs
  #46  
Old June 20th 18, 06:51 PM posted to rec.photo.digital
Carlos E.R.
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Posts: 278
Default Meaning of ISO value in digital photography?

On 2018-06-20 16:05, Whisky-dave wrote:
On Wednesday, 20 June 2018 10:48:09 UTC+1, Carlos E.R. wrote:
On 2018-06-20 11:17, Whisky-dave wrote:
On Wednesday, 20 June 2018 09:12:40 UTC+1, Sandman wrote:
In article , Jim-P wrote:

In film cameras, ISO referrs to the sensitivity to light of the
emulsion. Manufacturers formulate different film emulsions with
different sensitivites tarding increased grain with increased ISO
speed.

In a digital camera, presumably the sensor does not adjust itself to
have greater sensitivity. Or does it?

So what is happening in a digital camera when I choose a greater ISO
setting? Is more amplification being used?

Short answer: yup.

ISO for film and "ISO" for digital sensor has very little in common.

I thought they had quite a lot in common as it stands for International Standards Organization which covers light sensitivity of a sensor or film doesn't matter which.

That's what it means by a standard, previously film was ASA which was american while Europe used DIN , so a new standard was created for everyone with digital or film and it was called ISO not to be confused with ios of course.


I would think that a film camera loaded with film of a certain iso
rating and a digital camera adjusted to that same iso rating do a
similarly lighted photo when adjusted to the same diaphragm and shutter
speed, so that a photographer can adjust both with the same settings
using the same handheld light measurement instrument.


That is the general idea similar to any standard.

Previously germany and some of europe had the DIN standad for film speeds in the 1930s.
DIN 18 was 50 ASA or 50 ISO.


Many cameras and most rolls had both units here. Actually, DIN and ASA
rather than ISO.

By the way, I don't know what ASA means, can't decide on the Wikipedia page:

https://en.wikipedia.org/wiki/ASA

Could be "American Standards Association".

Ah, it is he

https://en.wikipedia.org/wiki/Film_speed#ASA

ASA aka ANSI

--
Cheers, Carlos.
  #47  
Old June 21st 18, 05:07 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default Meaning of ISO value in digital photography?

On Wed, 20 Jun 2018 02:17:50 -0700 (PDT), Whisky-dave
wrote:

On Wednesday, 20 June 2018 09:12:40 UTC+1, Sandman wrote:
In article , Jim-P wrote:

In film cameras, ISO referrs to the sensitivity to light of the
emulsion. Manufacturers formulate different film emulsions with
different sensitivites tarding increased grain with increased ISO
speed.


In a digital camera, presumably the sensor does not adjust itself to
have greater sensitivity. Or does it?


So what is happening in a digital camera when I choose a greater ISO
setting? Is more amplification being used?


Short answer: yup.

ISO for film and "ISO" for digital sensor has very little in common.


I thought they had quite a lot in common as it stands for International Standards Organization which covers light sensitivity of a sensor or film doesn't matter which.

That's what it means by a standard, previously film was ASA which was american while Europe used DIN , so a new standard was created for everyone with digital or film and it was called ISO not to be confused with ios of course.

Before the ASA standard most film was rated in Weston and DIN. See
https://en.wikipedia.org/wiki/Film_speed#Weston
--

Regards,

Eric Stevens
  #48  
Old June 21st 18, 10:51 AM posted to rec.photo.digital
Sandman
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Posts: 5,467
Default Meaning of ISO value in digital photography?

In article , Whisky-
dave wrote:

Jim-P:
In film cameras, ISO referrs to the sensitivity to light of the
emulsion. Manufacturers formulate different film emulsions with
different sensitivites tarding increased grain with increased
ISO speed. In a digital camera, presumably the sensor does not
adjust itself to have greater sensitivity. Or does it? So what
is happening in a digital camera when I choose a greater ISO
setting? Is more amplification being used?


Sandman:
Short answer: yup. ISO for film and "ISO" for digital sensor has
very little in common.


I thought they had quite a lot in common


Then you thought wrong.

--
Sandman
  #49  
Old June 21st 18, 11:11 AM posted to rec.photo.digital
Carlos E.R.
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Posts: 278
Default Meaning of ISO value in digital photography?

On 2018-06-21 11:04, Whisky-dave wrote:
On Thursday, 21 June 2018 05:07:29 UTC+1, Eric Stevens wrote:
On Wed, 20 Jun 2018 02:17:50 -0700 (PDT), Whisky-dave
wrote:



Before the ASA standard most film was rated in Weston and DIN. See
https://en.wikipedia.org/wiki/Film_speed#Weston


That was a bit before my time so I never really experienced it.

I did find my first exposure meter the other day, well a bit of it, think the make was sekonda or similar and it used a CDs cell I think, it had a needle and a dial and a little plastic cream shutter that rolled over the sensor.
Next time it re-appears I'll have to photograph it.


The description matches one my father had. I have it somewhere, but he
had to stop using it when the calibration went wrong and we did not know
how to mend it. It used no batteries.

The leather pouch is labelled sixtomat. The device itself lost the
label. The needle doesn't move anymore. On the rear it has a "color
finder" thing, name "Gossen". It is for finding the colour temperature.
It says my led lights on my desk give 2600, while the room ones give
perhaps 4000. It was for "cine" ussage, I think.

There are photos on google. Seems to be this one:
http://www.camarassinfronteras.com/accesorios/sixtomat/sixtomat.html
but my pouch is different.


--
Cheers, Carlos.
  #50  
Old June 21st 18, 02:39 PM posted to rec.photo.digital
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Posts: 24,165
Default Meaning of ISO value in digital photography?

In article ,
Sandman wrote:

Jim-P:
In film cameras, ISO referrs to the sensitivity to light of the
emulsion. Manufacturers formulate different film emulsions with
different sensitivites tarding increased grain with increased
ISO speed. In a digital camera, presumably the sensor does not
adjust itself to have greater sensitivity. Or does it? So what
is happening in a digital camera when I choose a greater ISO
setting? Is more amplification being used?

Sandman:
Short answer: yup. ISO for film and "ISO" for digital sensor has
very little in common.


I thought they had quite a lot in common


Then you thought wrong.


nope. he is correct. you are not.
 




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