Is the term ISO “totally fake”?

justaCanonuser

Grab your camera, go out and shoot!
Feb 12, 2014
358
199
Frankfurt, Germany
Armature disclaimer (you get what you pay for):

1- ISO in-variance still hits the wall of clipping. One you've filled your light bucket, there is no way to recover that information.
Digital & film shooter disclaimer: that's still a nice thing about negative film, it is much more forgiving in the highlights, there is no harsh clipping.
 
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justaCanonuser

Grab your camera, go out and shoot!
Feb 12, 2014
358
199
Frankfurt, Germany
I am not surprised about Tony Northrup's examples and conclusion. We have both a Canon and Nikon system, and noticed already several years ago that there is always a difference of 1/3 (or more) of a stop in the results of our Canon and Nikon digital cameras, using the same settings. Since Canon installed "Auto-ISO", I used that and stopped thinking about ISO when I shoot digital, I only think in the categories of less or more noise.

I think ISO (if correctly implemented) made some sense in those days back when a lot of experienced photographers went digital, because it helped them to get a certain feeling for the digital work-flow. But that's over now, Tony N. is definitely right.
 

flip314

EOS 80D
Sep 26, 2018
117
115
Digital & film shooter disclaimer: that's still a nice thing about negative film, it is much more forgiving in the highlights, there is no harsh clipping.
I wish Canon had some way of protecting highlights better. On my 80D I almost always shoot at -2/3 exposure compensation because otherwise there's likely to be some area that blows out.

I can think of some ways to do it with extra features per pixel (for example one more and one less sensitive photodiode, or a ways to let excess charge spill over into a large capacitor), but they're likely to compromise the overall performance of the sensor due to the area they'd take up. It would also add to the processing burden, an area where Canon already seems weak.
 

rjbray01

EOS T7i
Jan 19, 2017
88
38
Thank you for speaking my mind. When I was first getting started in the publishing industry I knew a staff photographer just like him. That guy knew -or felt he knew- a lot about photography and would talk your ear off about it. We actually had a handful of good conversations about it over the years. However, he ultimately lost his job to me because he couldn't actually take photos with a camera. He just knew the technical aspects of it but editors would constantly complain about the images he delivered to them. (He had several...MANY reshoots over his tenure there.)

Focusing too much on the technical side of photography can't be fun. I have seen plenty of photos the Northrups share on their channel to know that they are THAT guy I worked with. They know a lot about the technical side of photography - enough to be dangerous - but they may lack the creativity and ability to be successful photographers beyond the stock photography business they had.
Tony would probably be the first to agree with you ... he isn't selling himself as a great photographer .. he's in the "infotainment" industry ... and judging by his number of subscribers he seems to be doing pretty well at it !
 

Diko

7 fps...
Apr 27, 2011
429
4
36
Sofia, Bulgaria
Both of them are right and wrong in the same time. Depending on the point of view.

What Tony does is to base his claims from the historical perspective of ISO. What current manufacturers do is on ISO 100 they stay with a base multiplication of electrons/photons count by zero (probably). On the other hand their tests are totally faulty. Neither of them did offered an image which would put to the test dynamic range which is as you know in correlation with the ISO. This actually is the most important aspect of this dispute.

In their tests both should have offered to the viewers deep shadows and drastic highlights and to check how much information is available after performing the tests with different settings.

I'm trying really very hard to imagine how would I find the difference between Canon 40D, Canon 5D4 or a CCD Hasselblad. You see, with the first and the last one you really are getting in dangerous territories with an ISO of 1600. Especially when looking for information from dark images. These days however with more recent models we know that this frontier has been crossed. And this is what it all counts for that in the end of the day I now that may be in a specific place by specific like conditions before I wasn't able to do and deliver what I can now.

Probably Tony could be right for one think they could have been talking to us with the gain which is a relative kind measuring because it's not the same again with different sensors In different camera setups. However from historical perspective even if the vendors would go the route where they would lower the ISO numbering that wouldn't help us to measure any advantage from the days before. The St. triangle wouldn't be a triangle anymore. It takes time and devotion to learn by heart (and I'm not speaking of understanding and knowing but feeling and getting used to like driving a car) the correct settings of manual photo shooting. You want to get rid of one part of it which from my current perspective would be much more confusing. But I don't know if I'm right because I am so used to it now.


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privatebydesign

Would you take advice from a cartoons stuffed toy?
Jan 29, 2011
7,381
384
119
Digital & film shooter disclaimer: that's still a nice thing about negative film, it is much more forgiving in the highlights, there is no harsh clipping.
Not really true. Once you over expose film it holds no detail it is just base emulsion and the dynamic range of all current digital cameras comfortably beats the dynamic range of even the best commonly available films.

Now it is true that the exposure response curves of film don’t have the linear nature that digital captures do, but that is why a gamma curve is applied to every RAW image file, adjust that gamma curve and the highlight falloff is just the same as film. Digital did get a very bad reputation for blown highlights years ago because the dr was comparatively limited and it was very easy to not expose optimally for the medium, that is expose for the highlights which means most accurate exposures appear under exposed.
 

eosuser1234

EOS 80D
Jul 16, 2013
136
18
Japan.
It is technically eliminated when you put ISO to auto, and set your shutter speed and aperture to what ever you want in manual mode.
 

Kit.

EOS 6D MK II
Apr 25, 2011
817
327
Not really true. Once you over expose film it holds no detail it is just base emulsion
For the negative, it's the other way around.

and the dynamic range of all current digital cameras comfortably beats the dynamic range of even the best commonly available films.
Actually, according to the data sheets, the dynamic range of Fuji's moderate-contrast negative film (Reala, NPC/NPH, 160C/400H) is about the same (if not better) as the DR of the 6D2/RP sensor.
 

privatebydesign

Would you take advice from a cartoons stuffed toy?
Jan 29, 2011
7,381
384
119
For the negative, it's the other way around.


Actually, according to the data sheets, the dynamic range of Fuji's moderate-contrast negative film (Reala, NPC/NPH, 160C/400H) is about the same (if not better) as the DR of the 6D2/RP sensor.
Sorry yes, I was thinking positive and negative film at the same time, I shot mostly slide film but I should have been more clear.

The 6D MkII and RP are probably the cameras with the lowest DR available today and the sensor is over 6 years old, whilst they are, I admit, “current digital cameras” I suppose I should have said current sensor technology.

Even so I think my points were valid. Digital used to have bad DR compared to film so got an undeserved reputation, especially in the highlights, because people didn’t expose it correctly. Digital and film have fundamentally different recording characteristics but if you understand what they are there is no effective advantage, technically, of one over the other. Digital cameras with modern specs have long outgrown the earlier generations of digital cameras and are every bit as capable, and generally better, of recording scenes as film was/is.

That does not mean I don’t believe film has value or a place in photography, it also doesn’t mean using film cameras doesn’t have a certain style and feel that can infuse itself into the final image.
 
Aug 21, 2012
6
0
I'm mainly inteested in cinematography. In the C-series cameras, Canon has documented (in their whitepapers) that there is analog gain applied (prior to raw recording) that varies with ISO setting. That gain is .5x below 850ISO (C300) and rises above that setting. So, for these cameras (and I assume others) ISO is 'real' in the sense that it materially changes what is recorded in a way that cannot be changed in post processing.

This point is usually discussed in relationship to stops above and below middle gray (and DR) that are recordable at various ISO settings. In other words, the concrete impact ISO has on results.
 

tallrob

EOS M50
Apr 24, 2013
30
1
Sure, you could debunk any standard of measurement you want by the same methods. The kilopascal (kpa) is totally fake because it's different at one elevation than it is at another. Mph is fake because it's relevant to the speed of other moving objects. A pound only weighs a pound in a vacuum.

ISO is a measurement of light sensitivity and/or gain. Just because some camera's light meters are bad doesn't make it less relevant. Why do people try to get attention by convincing stupid people they can debunk traditional photography standards? Oh yeah, page hits fuel ad revenue. Bingo.
 
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3kramd5

EOS 5D MK IV
Mar 2, 2012
2,897
283
I wish camera manufacturers would call sensitivity and gain by their names, and use proper units. And use a logarithmic scale instead of ridiculous large numbers.
The intent of the ISO standard governing digital camera speed ratings is to harmonize digital with film. I suppose camera makers could put a gain control knob in dB on cameras, but the ISO paradigm is well understood and established.
 
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justaCanonuser

Grab your camera, go out and shoot!
Feb 12, 2014
358
199
Frankfurt, Germany
Sorry yes, I was thinking positive and negative film at the same time, I shot mostly slide film but I should have been more clear.
I didn't mean positive (slide) film, such a film isn't very forgiving and needs careful metering, of course. But in particular many negative b&w films have a lot of latitude in the highlights. I know what I am speaking about, because I still shoot and develop films by myself, aside digital photography.
 

Don Haines

Beware of cats with laser eyes!
Jun 4, 2012
7,877
1,209
Canada
It is an approximation. It is a scale that compares a digital interpretation of an analog reading of a photo-electronic phenomenon to that of chemical processing of a photo-chemical reaction that is time and temperature sensitive, where both sides of the comparison are rounded to a set of standard numbers.

Anyone looking for exact results will be sorely disappointed. You are comparing something that is somewhat close to X (within about 50percent) against something that is somewhat close to Y (also within about 50 percent) and getting upset that they are not the same.
 

epsiloneri

EOS 7D MK II
Aug 26, 2010
421
0
Not "A/D converted", but "converted to voltage range". A/D converters (which then convert a voltage value from this range to a binary code) are usually still one per row (or column), one per chip or even off-chip.
Yes, thanks for the correction. Each pixel is readout with its own amplifier, with typically one or two ADC per column/row. Per-pixl ADC are still experimental.
 

3kramd5

EOS 5D MK IV
Mar 2, 2012
2,897
283
Yes, thanks for the correction. Each pixel is readout with its own amplifier, with typically one or two ADC per column/row. Per-pixl ADC are still experimental.
Per pixel amplifier? Do you have a schematic for that?