Olympus UK E-System User Group
Olympus UK E-System User Group

Join our unique resource for Olympus Four Thirds E-System DSLR and Pen and OM-D Micro Four Thirds photographers. Show your images via our free e-group photo gallery. Please read the e-group.uk.net forum terms and conditions before posting for the first time. Above all, welcome!


Go Back   Olympus UK E-System User Group > General photography discussion

General photography discussion Please look for a specific board to start your thread but if you can't find an appropriate one, post it here.

Reply
 
Thread Tools Display Modes
  #1  
Old 15th March 2019
wornish's Avatar
wornish wornish is offline
Senior Member
 
Join Date: Sep 2015
Location: Cheshire
Posts: 5,774
Thanks: 326
Thanked 528 Times in 408 Posts
Likes: 2,684
Liked 1,521 Times in 752 Posts
ISO is Fake - Seriously

Very interesting video from Tony Northrop. OK perhaps its clickbait but nevertheless he does make a point and Oly come out as one of the worst offenders.


https://www.youtube.com/watch?time_c...&v=QVuI89YWAsw
__________________
Dave

My Flickr
Reply With Quote
  #2  
Old 15th March 2019
Naughty Nigel's Avatar
Naughty Nigel Naughty Nigel is offline
Full member
 
Join Date: May 2008
Location: Land of the Prince Bishops
Posts: 9,557
Thanks: 385
Thanked 547 Times in 462 Posts
Likes: 3,316
Liked 2,279 Times in 1,506 Posts
Re: ISO is Fake - Seriously

There is nothing new in that. Compact cameras in particular have often reported wildly optimistic ISO speeds to help keep noise down.

Unlike film a digital camera is effectively a closed system so it can report whatever ISO it likes as long as the exposure is about right.
__________________
---------------

Naughty Nigel


Difficult is worth doing
Reply With Quote
  #3  
Old 15th March 2019
Petrochemist Petrochemist is offline
Full member
 
Join Date: Apr 2015
Location: N Essex
Posts: 727
Thanks: 36
Thanked 81 Times in 74 Posts
Likes: 212
Liked 126 Times in 92 Posts
Re: ISO is Fake - Seriously

The ISO values many of today's cameras reach are above any defined in any ISO standards. I suspect the problem is the length of time it takes to approve ISO methods, which is generally many years.
__________________
Mike
Compulsive photographic Dabbler.
Flickr
Reply With Quote
  #4  
Old 15th March 2019
Naughty Nigel's Avatar
Naughty Nigel Naughty Nigel is offline
Full member
 
Join Date: May 2008
Location: Land of the Prince Bishops
Posts: 9,557
Thanks: 385
Thanked 547 Times in 462 Posts
Likes: 3,316
Liked 2,279 Times in 1,506 Posts
Re: ISO is Fake - Seriously

Quote:
Originally Posted by Petrochemist View Post
The ISO values many of today's cameras reach are above any defined in any ISO standards. I suspect the problem is the length of time it takes to approve ISO methods, which is generally many years.
Surely the ISO sensitivity of a film or digital camera is a logarithmic function, so it is simply calculated from a standard of (say) 100?
__________________
---------------

Naughty Nigel


Difficult is worth doing
Reply With Quote
  #5  
Old 19th March 2019
Petrochemist Petrochemist is offline
Full member
 
Join Date: Apr 2015
Location: N Essex
Posts: 727
Thanks: 36
Thanked 81 Times in 74 Posts
Likes: 212
Liked 126 Times in 92 Posts
Re: ISO is Fake - Seriously

Quote:
Originally Posted by Naughty Nigel View Post
Surely the ISO sensitivity of a film or digital camera is a logarithmic function, so it is simply calculated from a standard of (say) 100?
The DIN part of the scale which is the bit after the slash & frequently left off is actually the logarithmic part, while the ASA portion is Linear. The speed you referred to is officially ISO 100/21


Ignoring that (as everyone now ignore the DIN bit),If it's as simple as that why has ISO produced so many methods for doing it?

There's:
ISO 6:1993 for Black & white film
ISO 2240:2003 for colour slide film
ISO 5880:2001 for colour negative film
& ISO 12236:2019 for digital cameras
I've not heard of the revisions to the 2006 version of ISO12236, but that had FIVE different procedures, that didn't give the same results.

The Wikipedia page (https://en.wikipedia.org/wiki/Film_speed) is quite interesting if you want more technical details.
https://www.iso.org/obp/ui/#iso:std:...232:ed-3:v1:en gives a preview of the new version of the standard. Possibly only FOUR procedures with the deletion of Annex E.


Less relevant perhaps we also have:
ISO 2720 for exposure meters
ISO 2721 for camera auto metering
ISO 5763 for flash
ISO 7187 for direct positive colour film
ISO 10157 for flash meters
__________________
Mike
Compulsive photographic Dabbler.
Flickr

Last edited by Petrochemist; 19th March 2019 at 11:57 AM.
Reply With Quote
  #6  
Old 15th March 2019
Ian's Avatar
Ian Ian is online now
Administrator
 
Join Date: Jul 2007
Location: Hemel Hempstead, Hertfordshire, UK
Posts: 11,565
Thanks: 421
Thanked 2,522 Times in 1,269 Posts
Likes: 862
Liked 1,693 Times in 768 Posts
Re: ISO is Fake - Seriously

There are two different industry standard interpretations of ISO calibration (at least).

Ian
__________________
Founder and editor of:
Olympus UK E-System User Group (http://e-group.uk.net)
Four Thirds User (http://fourthirds-user.com)
Digital Photography Now (http://dpnow.com)
Olympus camera, lens, and accessory hire (http://e-group.uk.net/hire)

Twitter: www.twitter.com/ian_burley
Flickr: www.flickr.com/photos/dpnow/
Pinterest: www.pinterest.com/ianburley/
NEW: My personal BLOG ianburley.com
Reply With Quote
  #7  
Old 15th March 2019
Graham_of_Rainham's Avatar
Graham_of_Rainham Graham_of_Rainham is offline
Administrator
 
Join Date: Nov 2007
Location: Rainham
Posts: 8,103
Thanks: 642
Thanked 939 Times in 727 Posts
Likes: 2,263
Liked 1,580 Times in 910 Posts
Re: ISO is Fake - Seriously

https://www.dxomark.com/About/In-dep...SO-sensitivity
__________________
Graham

We often repeat the mistakes we most enjoy...
Reply With Quote
  #8  
Old 16th March 2019
Petrochemist Petrochemist is offline
Full member
 
Join Date: Apr 2015
Location: N Essex
Posts: 727
Thanks: 36
Thanked 81 Times in 74 Posts
Likes: 212
Liked 126 Times in 92 Posts
Re: ISO is Fake - Seriously

Quote:
Originally Posted by Ian View Post
There are two different industry standard interpretations of ISO calibration (at least).

Ian
I know of two for film:
ISO 5800 for colour negative
ISO2240 for Black & white


For digital we have ISO 12232 which apparently has 5 different techniques that can give different results. There were no official speed designations above ISO10,000 in the 2006 release, a new 2019 version is now available I don't know how significant the changes are.



Oh and it seems several high sensitivity films were marketed as having higher ISO than the standards gave... https://en.wikipedia.org/wiki/Film_speed
__________________
Mike
Compulsive photographic Dabbler.
Flickr
Reply With Quote
  #9  
Old 15th March 2019
Tram Tram is offline
Full member
 
Join Date: Jul 2018
Location: United Kingdom
Posts: 337
Thanks: 18
Thanked 31 Times in 28 Posts
Likes: 26
Liked 110 Times in 73 Posts
Re: ISO is Fake - Seriously

Shouldn't ISO be a standardised unit?
Can see problems for those who need it to be such as metering in a studio type setting.

Not much of a problem for the likes of myself who uses it in a less measured way.
Reply With Quote
  #10  
Old 15th March 2019
pdk42's Avatar
pdk42 pdk42 is offline
Full member
 
Join Date: Apr 2013
Location: Leamington Spa
Posts: 5,710
Thanks: 370
Thanked 1,257 Times in 942 Posts
Likes: 150
Liked 5,995 Times in 1,953 Posts
Re: ISO is Fake - Seriously

It's a nonsense video. Measuring ISO on digital cameras is highly open to interpretation, and as Ian says there are at least two "standard" ways of doing it. Honestly, TN is just a click-bait merchant. Avoid him.
__________________
Paul
E-M1ii, Pen-F and too many lenses
flickr
Portfolio Site
Instagram
Reply With Quote
  #11  
Old 15th March 2019
wornish's Avatar
wornish wornish is offline
Senior Member
 
Join Date: Sep 2015
Location: Cheshire
Posts: 5,774
Thanks: 326
Thanked 528 Times in 408 Posts
Likes: 2,684
Liked 1,521 Times in 752 Posts
Re: ISO is Fake - Seriously

Quote:
Originally Posted by pdk42 View Post
It's a nonsense video. Measuring ISO on digital cameras is highly open to interpretation, and as Ian says there are at least two "standard" ways of doing it. Honestly, TN is just a click-bait merchant. Avoid him.

What does he say that is nonsense? Please share, I genuinely don't know where you get that from? Did you actually watch it?

The basic point is that ISO on a digital camera is not a standard despite what manufacturers try and convince us it is. On Astro cameras they are honest and simply call it Gain.

Yes, Tony does create clickbait but at least if you are going to be critical have some facts that prove he is wrong.
__________________
Dave

My Flickr
Reply With Quote
  #12  
Old 15th March 2019
Naughty Nigel's Avatar
Naughty Nigel Naughty Nigel is offline
Full member
 
Join Date: May 2008
Location: Land of the Prince Bishops
Posts: 9,557
Thanks: 385
Thanked 547 Times in 462 Posts
Likes: 3,316
Liked 2,279 Times in 1,506 Posts
Re: ISO is Fake - Seriously

Quote:
Originally Posted by wornish View Post
The basic point is that ISO on a digital camera is not a standard despite what manufacturers try and convince us it is. On Astro cameras they are honest and simply call it Gain.
That is exactly what I said.
__________________
---------------

Naughty Nigel


Difficult is worth doing
Reply With Quote
  #13  
Old 16th March 2019
pdk42's Avatar
pdk42 pdk42 is offline
Full member
 
Join Date: Apr 2013
Location: Leamington Spa
Posts: 5,710
Thanks: 370
Thanked 1,257 Times in 942 Posts
Likes: 150
Liked 5,995 Times in 1,953 Posts
Re: ISO is Fake - Seriously

Quote:
Originally Posted by wornish View Post
What does he say that is nonsense? Please share, I genuinely don't know where you get that from? Did you actually watch it?

The basic point is that ISO on a digital camera is not a standard despite what manufacturers try and convince us it is. On Astro cameras they are honest and simply call it Gain.

Yes, Tony does create clickbait but at least if you are going to be critical have some facts that prove he is wrong.
The problem with the video is that he's just doing a subjective viewing of the image brightness and of course the final brightness will be subject to all sorts of processing changes. I don't doubt that different cameras (and processing) can produce different final brightness for a specific ISO setting, but Tony's conclusion is simply that the ISO is "wrong". That's just a huge oversimplification and he states it simply to gain clicks and feed the ignorant.

For film, it's easy to measure ISO since all you do is determine the exposure required to build a particular density on the emulsion after development. Of course, you need to calibrate the development process, the measuring eqpt etc, but that's all quite doable. For digital though, it's not at all so clear since the final image brightness can be manipulated within very wide margins after exposure. There are at least three approaches you could take:

- The exposure needed to saturate the sensor (clipping) can be used as the baseline. Then, the ISO is (somewhat arbitrarily) calculated as the light needed to produce a particular pixel saturation based on the reflected light from an 18% grey card at a given illumination level (i.e. what your Weston Master would tell you!). The standard is for that 18% grey to produce a 12.7% pixel saturation.

- The level of acceptable noise in the final image. In this test, the S/N ratio of the image is used to determine what an acceptable exposure is. There are two thresholds used for the S/N - 40:1 and 10:1, determined by subjective analysis of a particular print resolution and viewing distance.

- A so-called Standard Output Sensitivity test which measures the exposure needed to produce a specific bit value in an RGB file with a specific gamma. This will include all the processing that happens on a file and can be thought of as a "JPEG" measure.

Most manufacturers will use some combination of the above to arrive at a number, but there are other complications such as spectral characteristics and white balance settings which should also be taken into account.

The bottom line is that measuring ISO is complex and trying to claim that manufacturers are in some way misleading us is, well, misleading!
__________________
Paul
E-M1ii, Pen-F and too many lenses
flickr
Portfolio Site
Instagram
Reply With Quote
The Following User Liked This Post:
Otto (16th March 2019)
  #14  
Old 17th March 2019
birdboy birdboy is offline
Full member
 
Join Date: Jun 2011
Location: Essex
Posts: 1,366
Thanks: 345
Thanked 236 Times in 199 Posts
Likes: 180
Liked 325 Times in 157 Posts
Re: ISO is Fake - Seriously

Quote:
Originally Posted by wornish View Post
What does he say that is nonsense? Please share, I genuinely don't know where you get that from? Did you actually watch it?

The basic point is that ISO on a digital camera is not a standard despite what manufacturers try and convince us it is. On Astro cameras they are honest and simply call it Gain.

Yes, Tony does create clickbait but at least if you are going to be critical have some facts that prove he is wrong.
I would say that the video is misleading. As someone who is into astrophotography I have really tried to understand the ISO effect. From what I have read from trusted sources and books for Olympus cameras ISO is a pre ADC gain i.e it boosts the analogue voltage signal of the photon hitting the photo sensor. You cannot change the ISO once the image has been taken, you can change the brightness but not the ISO. If it was a gain post ADC you could change it. Now in astophotography (or very low light) only a few photons will be hitting the photo sensor. Read errors and ADC quantisation add noise after the ADC. If you kept the ISO at native ISO say 200 (Olympus) you will get more noise in your image than if you had upped the ISO to say 1600 (3x gain pre ADC). That is because the signal is more pre ADC therefore giving a better s/n ratio.

I am not sure if I have explained this that well But ISO in cameras is such a confusing and often misquoted issue.
__________________
John

OM-D E-M1, 12-40 f2.8 Pro, Tamron 14-150mm f5.8, E5, E3, Zuiko 50-200mm SWD, Zuiko 12-60mm SWD, Zuiko ED 70-300mm f5.6, 50mmf2, Zuiko ED 9-18mm f5.6, Sigma 50-500mm f6.3, EC14, EC20, RM-1, VA-1
Reply With Quote
The Following Users Liked This Post:
Ross the fiddler (17th March 2019), wornish (17th March 2019)
  #15  
Old 17th March 2019
Naughty Nigel's Avatar
Naughty Nigel Naughty Nigel is offline
Full member
 
Join Date: May 2008
Location: Land of the Prince Bishops
Posts: 9,557
Thanks: 385
Thanked 547 Times in 462 Posts
Likes: 3,316
Liked 2,279 Times in 1,506 Posts
Re: ISO is Fake - Seriously

Quote:
Originally Posted by birdboy View Post
You cannot change the ISO once the image has been taken, you can change the brightness but not the ISO.
How does ISO bracketing work then, when only one exposure is made?

Does the camera apply differing levels of gain to each image, with ISO numbers given accordingly?
__________________
---------------

Naughty Nigel


Difficult is worth doing
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Fake Email Alert Naughty Nigel The lounge 10 21st June 2017 07:32 PM
Fake batteries on tv tonight Olybirder The lounge 10 17th November 2015 10:59 AM
Fabulous or fake? Olybirder The lounge 17 26th May 2015 07:58 AM
Fake Infra Red In Lightroom OlyPaul Foto Fair 4 5th July 2014 11:41 AM
Is your camera a fake? Zuiko The lounge 2 26th August 2011 10:38 PM


All times are GMT. The time now is 11:03 PM.


The Write Technology Ltd, 2007-2019, All rights reservedAd Management plugin by RedTyger