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-   -   ISO is Fake - Seriously (https://e-group.uk.net/forum/showthread.php?t=50079)

wornish 15th March 2019 05:29 PM

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.:eek:


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

Naughty Nigel 15th March 2019 06:16 PM

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.

Petrochemist 15th March 2019 06:32 PM

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.

Ian 15th March 2019 06:42 PM

Re: ISO is Fake - Seriously
 
There are two different industry standard interpretations of ISO calibration (at least).

Ian

Graham_of_Rainham 15th March 2019 07:48 PM

Re: ISO is Fake - Seriously
 
https://www.dxomark.com/About/In-dep...SO-sensitivity

Tram 15th March 2019 07:51 PM

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.

Naughty Nigel 15th March 2019 08:51 PM

Re: ISO is Fake - Seriously
 
Quote:

Originally Posted by Petrochemist (Post 475135)
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?

pdk42 15th March 2019 09:11 PM

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.

wornish 15th March 2019 10:18 PM

Re: ISO is Fake - Seriously
 
Quote:

Originally Posted by pdk42 (Post 475169)
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.

Naughty Nigel 15th March 2019 10:46 PM

Re: ISO is Fake - Seriously
 
Quote:

Originally Posted by wornish (Post 475182)
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.

Bassman51 15th March 2019 10:52 PM

Re: ISO is Fake - Seriously
 
ISO is indeed a standard for digital camera jpgs, just as it was for negative and positive film. And just as happened in film days, different manufacturers’ ISO assignments for their products is a matter of judgement that is and was open to dispute by users.

Back in the day, some serious photogs would buy a brick of film (a bunch of rolls from one manufacturing lot) and use the first roll to carefully test and determine what the “real” ISO they would use for the rest of the brick.

Today, many digital cameras give us the opportunity to tune our view of their ISO to our liking by setting a permanent offset in the menu.

MJ224 15th March 2019 11:02 PM

Re: ISO is Fake - Seriously
 
As a not very techie in the camera world, I think you get used to what your camera does. In the old days, ISO 200 was good for sunshine, and 400 was good for something a bit duller and expected grain. ISO 25600 was beyond my comprehension, as it is today...ÖÖ...:confused:

Naughty Nigel 15th March 2019 11:11 PM

Re: ISO is Fake - Seriously
 
Quote:

Originally Posted by Bassman51 (Post 475184)
ISO is indeed a standard for digital camera jpgs, just as it was for negative and positive film. And just as happened in film days, different manufacturers’ ISO assignments for their products is a matter of judgement that is and was open to dispute by users.

Back in the day, some serious photogs would buy a brick of film (a bunch of rolls from one manufacturing lot) and use the first roll to carefully test and determine what the “real” ISO they would use for the rest of the brick.

Today, many digital cameras give us the opportunity to tune our view of their ISO to our liking by setting a permanent offset in the menu.

You are correct that the ISO standard applies to digital cameras (and not just Jpeg images) just as it does to film. However, the difference is that digital cameras often deviate wildly from that standard whereas better quality film cameras and light meters had to be within half a stop or so; especially if transparency films were being used.

In my experience any deviation in film cameras was fairly linear, so setting the film speed a third of a stop faster than rated was all that was needed to ensure perfect exposure and saturation when using transparencies. Even using consumer films I didn't find much variation from the clamed speed. (Negatives have massive exposure latitude so a stop either way didn't matter too much.)

However, in my experience once again, the true ISO sensitivity of digital cameras tends to be fairly close to the ISO standard at lower speeds, but falls a long way short at higher speeds; therefore providing much cleaner images than would be possible if ISO sensitivity was somewhere near what is should have been. That fact that current digital cameras provide a much wider range of ISO sensitivities only exacerbates this effect.

In my view this is little different to motor manufacturers who make false claims about fuel consumption or CO2/NOX emissions. In every case the deviation benefits the manufacturer more than the consumer, and is used as a selling tool.

Ross the fiddler 16th March 2019 12:39 AM

Re: ISO is Fake - Seriously
 
Quote:

Originally Posted by pdk42 (Post 475169)
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.

And that is totally why I won't even make an appropriate comment on the video, since I would only be adding to his 'click-bait' count.

Bassman51 16th March 2019 01:02 AM

Re: ISO is Fake - Seriously
 
Quote:

Originally Posted by Naughty Nigel (Post 475187)
You are correct that the ISO standard applies to digital cameras (and not just Jpeg images) just as it does to film. However, the difference is that digital cameras often deviate wildly from that standard whereas better quality film cameras and light meters had to be within half a stop or so; especially if transparency films were being used.

In my experience any deviation in film cameras was fairly linear, so setting the film speed a third of a stop faster than rated was all that was needed to ensure perfect exposure and saturation when using transparencies. Even using consumer films I didn't find much variation from the clamed speed. (Negatives have massive exposure latitude so a stop either way didn't matter too much.)

However, in my experience once again, the true ISO sensitivity of digital cameras tends to be fairly close to the ISO standard at lower speeds, but falls a long way short at higher speeds; therefore providing much cleaner images than would be possible if ISO sensitivity was somewhere near what is should have been. That fact that current digital cameras provide a much wider range of ISO sensitivities only exacerbates this effect.

In my view this is little different to motor manufacturers who make false claims about fuel consumption or CO2/NOX emissions. In every case the deviation benefits the manufacturer more than the consumer, and is used as a selling tool.

Iím never in favor of manufacturers (or others) lying about their products and services. At the same time, I expect a bit of sales hyperbole much of the time and donít rely on their claims, especially if they are about above-average performance compared to competing products.

I think the critical issue for us as users is rarely what the absolute ISO number is for a given camera/image, but rather whether the camera is capable of being used to produce images that we find properly exposed. All the digital cameras Iíve had in the last (say) 10 years meet that test. Sadly, I canít say the same for all the C-AF systems (Iím looking at you, Olympus). On the other hand, my recent cameras (E-M1, E-M1.2) significantly exceed the battery shot count in real life. Hereís a case where the testing protocol yields a number which is worse than I ever experience by more than a factor of two.

So my bottom line is: trust, but verify.


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