ISO Is Totally Fake

ISO is known as one of the exposure factors. The higher the ISO the more brightness. Camera manufacturers are even boasting about how high their ISO is going when they want to sell you a camera.

In this new video from Tony Northrup, he is explaining why ISO in modern cameras is fake. First things first, ISO is an international standard. ISO is an acronym for International Standard Organization. Back in the days of analogue cameras, they needed a standard for how sensitive film is to light. It would not make much sense to have two companies making two types of film, with different light sensitivity, calling both of them ISO 100.

Today many digital cameras are basically ISO-less. This is also called ISO invariance. It does not matter to the final photo whether you photograph it on ISO 100 or ISO 6400 given the shutter and aperture stays the same. Confused? Obviously, the ISO 6400 photo is brighter out of camera, but if you increase, the ISO 100 photo with the same amount of stops in post processing you will end up with the same amount of noise in the final photo as the ISO 6400.

As Northrup points out, that gives a potential for photos at ISO 3. Yes ISO 3. It is basically the same process as stacking images in post and averaging out the noise in the photo. Check an earlier article of mine to see how I apply this to my drone photos. What is really important for a clean photo is the "signal-to-noise ratio."

Check out the video above. If you are tech savvy this might not be new to you, but it is still very important to how you think about your settings when capturing your photo.

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Previous comments

YES! I was going to go through this exposition, but I saw you did it first. While I understand that the reporting of ISO for a given camera can be off, I don't agree with the basic argument Tony makes, for these exact reasons. I have checked several cameras against a calibrated light meter, and it's obvious you see differences between the stated ISO and the equivalent for the light meter readings, when making exposures manually. So I don't do that. What I care about is how much noise is in the image when I have very little light to work with. It's basically equivalent to the signal to noise ratio (SNR) in any circuit. Using multiple exposures is basically how we used to improve the SNR - not by averaging them, but by adding them. The random noise does not add but the signal does, so the SNR improves the longer you add the signal. Also, for sensors used in astrophotography, they cryogenically cool the sensor to remove the thermal noise and improve the SNR, while they are doing ultra long exposures. Anyway, who gives a crap? You learn what your camera can do and use it appropriately to record the data files that you eventually turn into photographs. Before I buy a new camera, I go to DXO and look at the sample images for different ISO settings and compare one sensor to another. It gives me a sense of how my images will look under the same circumstances. And you know what? If you stay in one class, the images are difficult to tell apart. $500 cameras look like this; $1500 cameras look better, and $3000 cameras look better still. Duh.

William Faucher's picture

Are we just going to ignore a key factor here? There is another thing that a lot of photographers are often unaware of, but filmmakers/video peeps will know about. T-Stops. Aperture/F-stops is a pretty arbitrary number. It doesn't measure how much light is let in. This is what a T-stop is. Canon 85mm 1.4 vs. Nikon 85mm 1.4 will have different T-Stops. One will let more light in than the other, resulting in a brighter exposure.

Just because the F-number is the same, doesn't mean the T-stop is. This is a huge factor. To say ISO doesn't matter is abhorrently wrong. You will not get the same result by boosting a shot at 100 ISO by 5 stops. A well exposed shot at 3200 ISO will result in far less noise, and substantially better color, though depending on your camera, your mileage may vary. Having done this test with my trusty D800, the shot at 3200 ISO is similar in noise, but the color is WAY better.

What Tony seems to be pointing out here is the flexibility of shooting RAW, nothing more.

I am happy to be proven wrong here, but until ALL VARIABLES are the same, none of these tests are accurate, they are downright misleading. Why is this even being shared on here?

And most importantly, if camera sensors were truly ISO-less, wouldn't that mean you could shoot a well-exposed image at ISO 3200, and have the same noise as a well-exposed ISO 100 shot? I don't think so.

Christopher Reddy's picture

Please check your facts - ISO does NOT stand for International Standards Organization - their website says:

"We're ISO, the International Organization for Standardization. We develop and publish International Standards."

That is the Organization, not the replacement for ASA - ISO is NOT an acronym - it comes from the Greek work isos meaning "equal" - more info here:

Rashad Hurani's picture

ISO guys are UN employees, don't take them seriously ;-) they also like to play this game with ISO Quality Standards. All what is named ISO is directly related to the Organization historically; now they want separation Brixet style!!

Mark Dunsmuir's picture

I've seen the use of the term ISO debated several times. I can't find the source at the moment, but, I've read about several members of the International Standards Organization who were contemporaneous to the naming say that the Greek / esoteric naming wasn't discussed at all during the early meetings. It's something that was applied to the term much later - a revisionist history so to speak.

Thomas H's picture

Aaaah, Toni is "at it" again, discovering "the obvious" and placing some stunning scandal or hype inducing title. How delightful, and still countless people take it serious. No, ISO is not a fake, total or otherwise.

Well, yea, in the film era by putting a different film we changed the recording medium.

A sensor is still the same, regardless the ISO setting. What is changing is the amplification of the signal and clearly also the recording time. Thus the difference between an image which is properly exposed and recorded at high ISO and underexposed image, which is than amplified in the post-process in the computer is the difference between hardware implementation of the amplifications, which may or may not be analog (!), with some noise reducing measures such as cross cell-filters and/or low pass filters, and a floating point multiplication (64bit presumably) on the raw file values performed in our computers. Some sensors appear to be "ISO invariant", like the Sony sensors in Nikon or Sony bodies mostly, others are not so. Watch Fstoppers own video to that very topic showing how the results differ. Not dramatically, but you should not stop to expose images properly in the camera and hope that you boost everything in the post-process.

Dirk Valcke's picture

I can understand the reason to 'dumb down' some concepts for a wide and varied audience, but i do think this was a too simple. Indeed, a sensor is not a film and that companies are taking a run with a standard is a pity for us photographers. It should be easy enough to define a DISO or digital ISO scale to standardize the rating given to ISO in digital devices (including a measurement of noise at the levels).

HaHa, another one from the genius Northrup...

Puffy Butter's picture

This article and Tony Northrop are wrong. Do some research and seek the opinion of experts before parroting shite from YouTube.

EL PIC's picture

Tony Northrup is Totally Fake !!

I couldn’t finish the video... I’m a tad confused by his testing method. He used three camera bodies and used the same settings, but it looks like he used three different lenses. I don’t know about the rest of you, I have an back up lenses for most of my bodies and so i’ve Noticed 1/2 to full stop differences between a 50mm prime and 24-70 set at 50mm. I even see the difference between to zooms of equivalent range by different manufacturers set to the same settings.

This topic has the smell of click bait to me.