Tony Northrup is WRONG about ISO!

ISO is Fake: • ISO is totally FAKE. S...
ISO In depth: • An in-depth look at ho...
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[@DaveMcKeegan]

I would like to apologise to Shaun @ F-stoppers - I said in this video that they agreed with Tony's findings, however I now realise that isn't the case. I misunderstood their interpretation of what Tony was suggesting and believed they were fully agreeing with him, having watched the video again since I realise they are actually more in line with what I am suggesting here. Sorry F-stoppers

[@TheEulerID]

I was going to raise that as the F-Stopper video did report visible differences between the underexposing 5 stops then boosting by 5 stops, even if they didn't know why.

[@FStoppers]

We have a new video coming out next that explores this even more. The results aren’t exactly what we would expect either! -P

[@DaveMcKeegan]

I look forward to seeing that. I am also aiming to put together a more comprehensive video looking at how the different kind of ISO works, hopefully we can all settle this debate 😁

[@Falcrist]

@@FStoppers I do wonder if there's a difference in how the image is processed. For example, I know the Sony Alpha series does noise reduction even on RAW files.

[@LE8271]

Not your fault. I had the same interpretation

[@geraldundone]

The biggest problem with this topic when trying to simplify it into a KZbin video is how it disregards just how camera-dependent this topic is. Tony went hard in one direction and I feel you might have gone a little too hard in other. For some cameras ISO is almost entirely digital gain and might as well be a metatag, because you can change it in post all day. For other cameras like many Canon models, changing ISO is not reversible in post and has serious consequences. For other cameras still, it's a hybrid where it's analog to a certain ISO and then a larger digital component at higher ISOs, and then fully digital in extended ISOs. The list goes on and on. The a7 III is a fun example because it does demonstrate invariance but at different steps like you mentioned. There's a lower stage from 100-640ish, and then from 800 onward. My point is it's all too camera-dependent to be making any claims about ISO in general, unless the claim is look how funky ISO is. And so, I didn't mind Tony's video because I felt like that was his key point. I also enjoyed your video because your counterpoints further demonstrated that it's not as simple as most would think. Cheers! 👍😃

[@DaveMcKeegan]

Thanks Gerald, we're all waiting for you to solve this issue once and for all 😁

[@geraldundone]

@@DaveMcKeegan You did a great job! The animations were great too!

[@DaveMcKeegan]

Thanks Gerald, that means a lot. I know it's a complex, camera dependent topic, and yes I probably did go a bit far in the opposite direction to try and balance out what Tony was saying. But the can of worms has been opened now 🤣 so think I might go for a more in depth video looking at the numerous different options and how they work

[@geraldundone]

@@DaveMcKeegan Here's a resource that might help you in your journey: www.photonstophotos.net/Charts/PDR_Shadow.htm#Sony%20ILCE-7M3 This one's for the a7 III, but they've charted a ton of cameras. Compare that to a Canon and you'll see what's going on.

[@halfphild]

@@DaveMcKeegan Please do! I really dig this information and like Gerald mentioned it seems like ISO is generally all over the place - These videos help us all at least try to understand what we're messing with. Cheers

[@MentalWhiplash]

It's amazing how many exceptional photographers execute their craft beautifully while remaining blissfully unaware of these debates.

[@odemata87]

Keywords exceptional photographers not supposed youtube influencers

[@butchjohnson9736]

@@odemata87 I don't think that most of the youtube photographers actually consider themselves to be great photographers. Jared Polin doesn't, the F-Stoppers don't, Matt Granger doesn't and the Northrup family consider themselves to be generalists without a particular expertise. So it's all good.

[@S3l3ct1ve]

No one really cares about these topic except the tech geeks and influencers who need to have a "topic" to talk about and generate view count. In short - each camera is different and each camera has different technology and different tweaking made to them.

[@clifftotten7609]

Many exceptional photos are taken on fully automatic settings too. If you just remember to use the lowest gain/ISO settings and expose using shutter speed and aperture as much as possible, you will be fine.

@@clifftotten7609: Your post is confusing. "... expose using shutter speed and aperture as much as possible..." does not match with "Many exceptional photos are taken on fully automatic settings too."

[@SamA-kl6pi]

Tony Northrop: keeping youtubers employed since 2014. This shit is gold.

[@melvinch]

And keeping fanboys brainwashed since 2014.

[@GuerillaWar4s]

Im pretty sure its not just the exposure the camera changes. Look at mobile cameras today. Software has already come a long way. How hard would it be to make one for a bigger camera?

[@melvinch]

@Steph Format the only stupid ones are those that defend liars.

[@geonerd]

Dave owes Tony a six pack!

[@TheBilly962]

@@melvinch Except attacking, trolling, being nasty and disrespectful - what is your purpose in this? I never ever read any explanation, argument, proper grown-up discussion fro your side. You are just nasty, petty wanna be "photographer" (even though I doubt it), who is seeking his 5 seconds of glory on forums. Your work and contribution are "fabulous" here and I will definitely try to find a way to get you of this social media.

[@DerVagabundli]

Coming from an audio background, I think iso is best understood as "gain". The lower the signal, the more the noise will be visible/audible when amping it. The lower your iso, the higher your signal to noise ratio. In audio, you try to get your signal input as high as possible without peaking. Basically with iso it's exactly the same. Only it's things like camera shake you're trying to avoid as well.

[@FairDinkumAussieBloke]

I was thinking very similar to you. It reminded me of my karaoke setup and how audio works

[@rickyjanzen6684]

Most video cameras used gain. Now, with the ISO craze, they have the option to use gain or ISO values. This bothers me a bit because every camera has a different "native ISO", so knowing X camera has the least grain at ISO Z, doesn't mean Y camera will have the lowest grain at ISO Z. But, they'll both have the lowest grain at 0db gain...

[@DerVagabundli]

@@rickyjanzen6684 in some ways the video guys definitely have the edge ✊

[@SmallSpoonBrigade]

In olden days, you could set the ISO setting, shutter and aperture based on a light meter based on film sensors and get a reasonable result. So, I'm not really sure what's changed. Although, it is worth noting that it never quite worked because digital sensors tend to blow out highlights in colors of red, yellow or magenta more so than film would. And you'd need to manually account for that if you've got any of those colors being directly lit, or you could wind up with unexpectedly blow areas in an image.

[@DerVagabundli]

@@SmallSpoonBrigade the difference is: on film, the ISO is the actual light sensitivity on the film. Changing the ISO just told the camera what film is loaded. All you could do was push or pull with a "wrong" setting. Now, the ISO setting boosts the Signal from the base iso, kind of like the gain on an amplifier. You still really only have your base ISO unless you have a camera with multiple base values (forgotten the term). But that's the reason why you have noise: the lower the light the higher the signal to noise ratio on your sensor, the more noise you get by bumping it up.

[@LDLCGO]

The problem is that not every iso step applies the same formula for analog gain/digital gain and this is different for every camera. Sometimes going from 200 to 400 applies digital gain and going from 400 to 800 dials back the digital gain and applies analog gain, thus the noise pattern in the shadows changes. Ideally you should test every iso in your camera to find the ones without digital gain and stick to those. Not only will it preserve dynamic range, but it'll force you to light your shots and/or choose an aperture that allows your camera to perform at it's best..

[@DrewMtl]

This is what I am curious about, thank you. so do you have a testing method for this? Or is there one provided some where and or do the camera manufacturers state their ideal iso setting? (should i set up a colour chart and photograph it with a metered setting to start and then go through my iso setting then apply post and see what setting needed the least amount of adjustment?

[@NewManToHandle]

I praise you, Tony and Gerald for even bringing this topic to discussion and debate! This was excellent education, and entertaining!

[@TacoTeaser]

I still like to use a hand held light meter,(Minolta 4A). I'm a waisting my time? Could there perhaps be a way to "calibrate" my camera ISO to my meters ASA settings?

[@NebulaPhotos]

This topic is something astrophotographers are well aware of since we are almost exclusively dealing with very low levels of signal and have to be very aware of what effect ISO has on noise. I think you explained the concepts very well for technically-minded beginners. What you are discussing starting at 04:10 is what astrophotographers call "read noise". Changing the ISO has typically been a balancing game between not increasing noise by setting the ISO too low, but maintaining enough dynamic range that one doesn't cripple color in brighter areas (for astrophotographers the stars). ISO-invariant cameras have been amazing because it means the ability to shoot at ISO 400 (more dynamic range) with still very low added read noise. I don't know of any serious astrophotographers shooting at ISO100 though for the reason you mentioned: no DSLR is truly "ISO-less" as that would mean zero read noise. My 2 cents.

[@CAYENNEOREZ]

In other words: For best results, know your camera. Thanks for the great explanation. The most important part of the video is one some people seem to be missing. Yes, ISO is applied gain, after the light hits the sensor (as Ken Wheeler might say) but it's applied gain BEFORE it goes to the converters and then the processor,, thereby amplifying it at it's purest state, without amplifying any of the noise associated with said converters and processor. Is that correct?

[@GreatKeny]

That is true. But when the noise associated with converter and processor gets very very minimal, amplifying the signal before or after becomes almost irrelevant. That's the whole idea of ISO invariance.

[@user-mm3xu2ts3j]

I did not understand how interference affects digital signal after ADs? What happens with the 1s and 0s?

[@janquieldapper]

One thing, and if you reduce noise in Lightroom in ISO 100? Is possible have the same results compare to ISO 800?

[@PaulKentSkates]

I was saying we need to standardize the lens (use the same lens adapted for each test camera) and test for shutter speed consistency. Good call on the sensor glass. Someone should do a scientific test.

[@TheNefastor]

I'm an electrical engineer and I do signal processing. Your video is very correct. Amplifying a signal before it's processed (known in the business as "sensor adaptation") is indeed going to prevent having to amplify the noise added by the whole processing chain. What Tony stated is equivalent to saying a digital zoom is just as good as an optical zoom : it's not, because the optical zoom scales up the picture before any processing, whereas the digital zoom must create pixels for which the original signal doesn't contain any data. Tony is a good source of a advice, but this is KZbin, world HQ of self-proclaimed experts. No matter how good someone seems to be, you had better double-check anything they say. Feel free to include me in the lot.

[@jethro606]

Hi Jean. In any precision electronic readout, you would like to be limited by the sensor's noise and get the most dynamic range out of it with the least amount of noise. So let's get paint this picture, the sensor generates some signal and some noise, and by default, we get a 8-bit signal out in the final picture. Which option is better: -Building a front end 2x amplifier that an input referred noise of half of the sensor and an 8 ENOB AD converter. -Build a 9 ENOB AD converter with an input referred noise of half of the sensor and decimate one of the bits for a 2x amplification in the digital domain. In both cases, we would end up with the same image in terms of SNR, and if we do smart choices for the AD design you can save significant area and power. If you check, manufacturers use 12-14bit SNR a/d converters, but each pixel generates a 8 bit information... that is just digital amplification, and if the noise level is sensor limited you are able to digitally "amplify" that information without losing any information. And that is pretty in accord to the image that the guy show, from ISO 100 to 12800 is around 16x but the SNR is not nearly 16x worse... one can quantize it but it is barely 2x worse, wich means you are 1 bit off in you adc... The digital zoom analogy is a bit off... if you happened to have a digital capture that is 2x better than what your eyes can even imagine to ever get, a 2x zoom would not result in any loss of information for you. And that is one point that the manufacturers play around, but with sensor noise. In the end manufacturers do play around a lot with pre amplification-dynamic range-digital quantization to get what they look for with conversion time/power/area/flexibility/SNR.

[@TheNefastor]

@@jethro606 you are splitting hairs my friend. I understand what you wrote, but who else does ? My comment wasn't aim at fellow engineers and in the strictest sense, you have to agree I'm correct. Taking into account parameters like the limitations of the human eye, for example, isn't really what we're discussing here 😉

[@otherside2k3]

I'm an electronics designer, specializing in mixed signal design and data acquisition. When I watched Tonys' Video I thought exactly the same... naaah there is no way that's true... I said to myself either there is some biasing on the sensor and the bias level is tuned for the ISO setting or there is a PGA in front of the ADC to sort of "auto adjust" the signal or set based on the ISO settings... Then i looked it up ... at least from the info i could find nope... nothing.. nada... of the cameras i could find some sort of block diagram or schematic there is no such stage... it is possible that Tony is correct... at least for some cameras

[@jethro606]

@@TheNefastor Hey, I know what I commented was not for everyone to understand, but I guess you would and I am fine with that. Also I would like to attract more of other engineers attention so they could correct me in the case. But if you got my point you would see that a pre amplifier is not always necessary. And like the other fellow said, you don't always find a front end PGA in such sensors because the ADC already bring noise levels so low that doing post digital amplification or analog amplification has nearly 0 difference. And that is what both guys showed in their videos, amplifying a signal 16x and not seeing 16x extra noise sort of means that.

[@TheFaustianMan]

Hello, I'm a male gigelo, I sleep with women for money.

[@DrewMtl]

What about camera ISO and grain/noise. which iso going to be best for least grain/noise? is the sensor starting point 100 and then it goes up or is it 400 (or another) and then it processes up or down from there internally. If light isn't my concern but image clarity is whats the best iso to be shooting at?

[@zakpearson7641]

Can someone help me out. What interference happens after digitization of the analog signal? Wouldn’t the noise you see from boosting the exposure in post come from digitization errors in the ADC rather than interference at some point after the digitization? Or am I off my rocker?

[@DaveMcKeegan]

It's not so much noise after digitisation but rather during because of quantisation - the figures it creates in digital aren't always exact matches to the analogue, when you then multiply the signal you also multiply the quantisation error

[@simatbirch]

I think Tony’s point still stands. FStoppers did actually see the colour shifts that you mention, but came to the conclusion (which I think is right) that for the difference seen the results are basically the same after post processing. I think Tony’s point was to educate people here and show them something that they may never have realised. It certainly opened my eyes on this. I don’t think Tony suddenly expects everyone to suddenly go out and shoot at ISO100 for a wedding reception without flash. His point is theoretical, and interesting.

[@DaveMcKeegan]

Except ISO and post processing are fundamentally different because one works on an analogue signal while one works on a digital ISO is like the preamps in audio equipment which will always yield better results than turning up the volume afterwards

[@amdphreak]

The ISO values should be adjusted to reflect the sensor’s light transmission factor. This is what the ISO measurement is supposed to measure. ISO is supposed to be a standard for how much light the sensor captures, AFTER TRANSMISSION FACTOR. Also, the point of the RAW format is to capture exactly the readout from the sensor, so the AD converter output should be identical between different ISO values, if the camera circuitry isn’t applying electrical amplification. If they are, it would seem of critical importance that the amps are very high quality. If they are not high quality, bumping up the exposure in software will be similar in noise level, but waveform-clipping artifacts would still be a problem.

[@SmallSpoonBrigade]

This is where I'm a bit skeptical. If the ISO we get in the camera is just in relation to the baseline for that particular sensor, then it won't be possible to use external meters without manually adjusting the readings, but I don't think that's the case. When I used to use an incidence light meter, I don't recall needing to adjust the output to compensate for the fact that I was shooting on a digital sensor.

[@AllMyHobbies]

my understanding is that when you shot higher iso the camera does some nose reduction without you even asking for it. when you boost the shots in lightroom are you adding more noses reduction for the lower iso ones?

[@jpsmith994]

Did you compare the histograms in your tests? Did you account dir adjusted highlights and shadows once pushed multiple stops

[@cogmission1]

You missed the main point (while making a few good points). Tony is *primarily* pointing out that camera manufacturers exploit the inaccuracy (and non-standard lack of uniformity) of ISO as a unit of sensitivity measurement; thereby allowing for more flattering ISO specification declarations. It is largely misleading, and that's what he's pointing out.

[@DaveMcKeegan]

Except it's always been like this, even back with film you would get variations in results from one brand to the next at the same ISO

[@KJ-md2wj]

Of course, but how many people know this, esp. beginners? The discussion here generated by Tony's video enlightened me about some cameras using a different tpye of amplifications at different ISO settings; before I thought it was a straight linear amplification. The manufacturers should be more open and tell us more about how they produce their raw files and JEPG's.

[@cogmission1]

@@DaveMcKeegan Yes! Also stated by Tony (re: "always been like this"). But I still think reviewers such as yourself keep peeps honest by monitoring the fringes of speech - so keep up the good work! :-)

[@dontgetmadgetwise4271]

Kind off you to speak for Tony. I am of the opinion that if Tony had wanted to say that he would have. But he didn't. He deserves full credit for obfuscation, inaccuracy and ignorance.

[@ChristiaanRoest79]

Agreed. Tony is 100% right.

[@markus8282]

Tony's video itself was the reaction to somebody else's video published one or two days before. I watched that also, but don't remember who it was. It was about higher DR with higher ISO at highlights and that ISO actually only is a parameter metadata at raw photos.

[@blakeaghili5033]

Sooooo ... Someone explain this to me: I shoot both film and digital at the same scene and use an external light meter ... so light meter reading could be wrong for digital?

[@hrabia]

so is it better to get right exposed photo with iso 6400 and get this noise than shoot it at 3200 or 1600 and retouch later?

[@DaveMcKeegan]

There is no benefit to shooting lower and retouching later - at best you'll end up with what you would have in camera and at worst the picture looks crap As long as you aren't clipping your highlights you'll be fine

[@michaelchandler5442]

ISO don’t care! Do we really think that camera manufacturers put a settings on the camera just so we could mess with one more knob? Think about it. This whole conversation is really out there. This is what I do know; Set the ISO as low as you can and shoot for correctly exposed image; Know your camera and know it’s limitations; Settings between cameras and settings even between models will vary; If it’s dark increase your shutter speed and open your f-stop and when you run out increase the ISO; You get what the light gives you and what the manufacturer provides. Nikon, Canon, Fuji and Sony all want you to be able to take the best picture possible. If the best solution was post software then they would provide that as a proprietary means of pushing your image. And they would drop the ISO setting. I don’t mind a good technology discussion, but this one is just absurd... to me!

[@deordered.]

i maintain my silence there because of chelsea...

[@PhotoTubeUK]

The Northrup channel would be much better if Tony left :)

[@sundarAKintelart]

I get the point. Haha 😄

[@the.picturepoet]

😅🤣😂

[@codezionjr]

I just keep ISO at Auto and adjust exposure compensation while shooting in Aperture Priority. Just a casual shooter. Am I doing something wrong? =)

[@6panel300]

Hi I have just returned to using a dslr after using a bridge camera for a few years (budget issue). I used to shoot with film cameras years ago before the digital revolution, when I used to buy film by what we called speed ratings or iso to give it a proper title. Now back then as you will know for general photos we would buy something like iso 100 and for sports photography iso 800. which was fairly simply as 800 was definitly more grainy than 100 so less desirable but allowed higher shutter speeds. now my problem is I can not see the difference between any of the iso settings on my pictures apart from what aperture and shutter settings I can use. is there an all round iso setting that I could use and leave it set on ie: iso 800 or I am I better off just leaving it set on auto. (sorry for the long question) ps I don't much post editing of my pictures.

[@DaveMcKeegan]

Modern cameras probably aren't as noticeable in the difference between iso 100 - 800 because of the improvements in tech Auto iso will get the job done to an extent provided the metering doesn't get confused and over / under expose your photo. Some cameras have an option in the menu to put a limiter on how high the auto iso can go

[@jeyycie3656]

To clarify what Dave said, on a CMOS sensor, which is now use on pretty much every camera, before the AD converter ( which is an independent componant of the sensor ), there's actually a charge converter included on each individual photosite of the sensor, which produce a voltage depending of the charge of the photosite, which can be then send to the AD converter. It's a little confusing, but without the charge converter for each photosite, it's not CMOS, it's a CCD sensor. ( IT CCD utilize lines of buffer photosite between normal one, and just serve as emptying active photosite, and transfering those charges to the charge converter, and then the AD converter. there is olso the FT version which use a second "sensor" that just serve as buffer, so that the active sensor have a better fill factor. )

[@MilutinLabudovic]

exactly, here is some old site about that from 2002 (the days CCD was the king of the picture and CMOS an unwanted baby), and light and color. very nice read. micro.magnet.fsu.edu/primer/digitalimaging/index.html

[@daehxxiD]

Finally, thanks for clearing this all up! I've read up on it all after Tony posted it the way he did, as it sounded really fishy. Your explanation now was definitely the easeiest to follow.

[@TheTempic]

Easy to follow but his main point is wrong. ISO invariant cameras do not boost an analog signal. It gets converted to digital pretty much right after light hits the sensel and the rest of the processing (including ISO) is on the digital part, so it can be altered later.

[@changleon7441]

Can you please clarify your specific procedures? Are you shooting in uncompressed RAW?

[@DaveMcKeegan]

Uncompressed RAW for all images. No in camera noise reduction of any kind Only post processing was the exposure in Lightroom to balance the images out

[@captinktm]

Great video. So I have a D610 which overexposes by two stops. So I control this with exposure compensation. My question is, is this better than adjusting the image in LR?

[@DaveMcKeegan]

You're probably better testing it out and comparing the results However I would say that as long as your shots are not clipping the highlights you're ok. It's generally better to shoot as bright as you can (without clipping the highlights) and pulling the exposure back rather than shooting underexposed and having to brighten it afterwards

[@w2.ill_]

This. I was so confused watching Tony’s video when he was talking about raising ISO in camera and in post being the same.

[@melvinch]

He has the talent of stirring shit and benefiting from it.

[@inpursuitofhappiness4873]

The real lesson here is never substitute gain for light, whether through ISO or in post. Choose slower shutter over higher ISO if the situation allows it. No?

[@MomentousGaming]

Depends, if you're shooting sports and need a sharp image, then ISO noise can be reduced in post a little, a blury subject can't.

[@lakehouse9164]

Just answer this for me. What is it that you can add to a digital or anolog signal to make it cleaner.

[@DaveMcKeegan]

You can't add stuff to a signal to make it clearer, it's more a question of not adding things to it to keep it clean

[@Veptis]

so a lot of cameras used in digital video cameras have dual native ISO, how do you explain that? is it in any way related to the HighGain and LowGain readout of some sensors?

[@DaveMcKeegan]

They have two separate circuits built into the sensor where a normal sensor would have one. The second circuit is optimised for the higher ISO, so rather than the camera boosting the signal from the lower ISO circuit like a normal camera, it just switches to taking the signal from the other circuit

[@videoslice2683]

digital is really just a single, reusable film frame (i.e. the sensor)

[@3439jc]

I think T&C wanted to give an elementary answer for the benefit of those beginners out there that need it broken down in an elementary way. I can appreciate that even though I'm not a beginner. Sometimes we forget how difficult is was to grasp certain understandings back when we first started out. Dave Mckeegan, great job and great info too.

[@melvinch]

That's is exactly the danger of his channel. He is misleading beginners ! You will learn more photographic truth from the Angry Photographer, backing up facts with optical principles. Phony Northrup on the other hand, mixed truths with lies that sounds believable for beginners.

[@williamneuman7783]

@@melvinch Oh please, the angry photographer is a hack. He talks and talks yet never backs up his word with any photo proof. At least T&C show their work when testing a camera or lens. All the angry photographer does is say trust me I know then does his weird laugh.

[@melvinch]

@@williamneuman7783 AP has photos on Flickr. They may not be artistic but are technically competent. Phony Northup's photos on the other hand, are amateurish at best. And I'm not the only one who think that way, you can google that. And most importantly, Phony Northrup has a fucking face that says "I'm a blatant Sony shill" written all over.

[@3439jc]

Well IF that's true I don't think it's intentional. Everyone is right in there own heart so I don't think it would be intentional. I personally haven't seen any issue where he was apsolutelly completelly wrong on an issue eather. With that said i know there's not a 100% of anything and so theres exceptions in every topic. Some people think that rair exceptions are the proof that someone is 180° wrong and that's just not the case even tho there is marriet in the accusation.

[@melvinch]

@@3439jc you're exactly the kind of supporter Phony Northrup depends on.

[@SebastianRocks1234]

What if you shoot ISO 80 but a low aperture like f2.1 and a high shutter speed like 1/8 second

[@MOAB-UT]

Great tips. I am pretty new to photography. Do you recommend Aperture Priority mode (Nikon D5500)? Mostly doing Landscapes. Also, what editing software do you like? I am thinking about Affinity and Neo. I am not a pro- just vacation pics. I do want Pano Stitching and HDR (hence Affinity.) Also, those two software packages are not overly complicated. I am in a demo of Affinity now. It's a little tricky but nothing like the learning curve with GIMP. These videos (and yours) really held. Thanks again!

[@lsdustyrhodes]

I think the point you make, Dave, that raising the ISO means that the camera boosts the analog signal before conversion to digital, is central to your argument. It totally makes sense, and would account for the increased noise (and also notice color shift as well) if one merely shoots at native ISO, then raising values during editing. Digitizing an analog signal always results in data loss: a curve is converted to a series of discrete steps, and that loss results in noise. Increasing exposure of a native ISO image during editing magnifies that noise; by boosting the signal (shooting higher ISO) before digitizing, you are retaining as much information as possible before the image is digitized: you are magnifying the analog curve, not the discrete steps. So the bits of noise are smaller and fewer. Fstoppers even remarked that they noticed more noise in the greatly underexposed native ISO image, but then blithely went on to ignore this observation, saying "Tony is right." I'm not a Tony fanboy, but like T&C, and Fstoppers too, but in this case, I think they're wrong, and I believe you explained why. Thanks, and good job.

[@barmalini]

Boosting the analogue signal before quantisation is indeed the central point. Dave has mentioned, though not stressed that quantisation is not a lossless process, it actually removes data from the analogue signal to be able to represent it in a digital form, so all the amplification is better to be done before that happens. Dave said "the interference" which is, in my eyes too soft of a term, because parts of data actually do get thrown away, not just interfered with. Also, and it has never been mentioned before, amplification of the analogue signal may, and probably does involve multiple stages like filtering, compression etc. Actually, the analogue part is exactly the place where the miracle of developing new sensors with better ISO range happens every year. Only that we, as a broad public are not aware of that fact. Well, just to summarize of what I've just said - Tony had represented a pixel as an empty bucket for collecting photons, connected to the input of a ADC, while in the reality it is, of course, much more complex, hence the mistake.

[@v0ldy54]

Apart from quantization noise (which isn't that big of a deal when you do the math) the biggest source of noise is the inaccuracy of the ADC itself, the so called "read noise". The Z6 perform great at high ISO because it has an extremely low read noise and good quantum efficiency being a BSI sensor, however at low ISO if you try to boost in post you will notice the different read noise between the normal pixels and those used for the AF, which results in the banding you can see when trying to open shadows 5-6 stops. At high ISO the difference in read noise is unnoticeable so the banding is completely swamped by other sources of noise and becomes completely irrelevant.

[@iAmTheSquidThing]

Yeah, it's like with digital audio. Before digitisation you want to get as much analog gain as possible without any clipping. If you recorded everything with 36 dB of headroom and then boosted it in post, you'd be wasting a whole lot of bit depth.

[@TheTempic]

The point is, that modern ISO invariant sensors do NOT boost the analog signal anymore. The analog/digtial converter is right behind the sensel wich brings other advantages too. This is the major flaw in this video. Analog amplification was performed on "older" sensors. This is also one reason why not every camera is ISO invariant.

[@toxictabasco]

Ha... they are pretty clever into getting views with viral content regardless if it' make logical sense.

[@Elemino]

I'm not saying you're wrong, just questioning how do you know they actually boost the voltage output vs applying some kind of denoise filter in or around the sensor?

[@ondoypordoy4143]

im just starting to take photos so just want to ask the differnece between brightness and iso?

[@DaveMcKeegan]

ISO is a method of brightening your photos, however there are other ways you can brighten your photos, i.e. with a wider aperture or longer shutter

[@ondoypordoy4143]

@@DaveMcKeegan thank you😘

[@DaveMacara89]

I bet Tony is laughing at how many people he has baited into making vidoes.

[@jeffreyd1962]

Absolutely! At the time of my reply Tony has over 232K views of his video while this guy only has nearly 73K views.... Views = $ …. This guy is getting Tony paid! Tony is laughing, alright- all the way to the bank!

[@DaveMcKeegan]

Tony would have had that many views with or without my video I doubt many people will be watching my video who hadn't already seen Tony's

[@clifftotten7609]

Tony is NOT baiting anybody! There is a TON of real misunderstanding about what GAIN actually is. Actually, the ISO term was fine in film but it doesnt belong in analog/digital sensors! In fact, the ISO concept is screwing photographers up today. Gain/ISO has nothing to do with exposure of light to a photosite. Only shutter and apertute controll "exposure".....NOT gain/ISO. The faster people understand this, the better we all are.

[@deviceundertest]

@@DaveMcKeegan Tony's video should be reported as fake news and removed, spreading untrue information, comparable to 'earth is flat'.

[@marksummers5504]

Laughing to the bank

[@rallisf1]

Great job describing how ISO works, as an engineer "sensor sensitivity" felt wrong but that's how everybody describes ISO and if it wasn't for Tony's boldness & ignorance many people would still be clueless. Should we flame Tony for not knowing what a DAC is and how signals work in electronics? Hell no, I pretty much like his content and we are all evolving here. It's actually very nice of youtubers to step up and put each others concepts in the test, that's how science works; you publish an idea and expect others to (dis)prove it.

[@henri.witteveen]

I assume you mean ADC instead of a DAC.

[@rallisf1]

@@henri.witteveen the point is none cares except the engineers and frankly I wouldn't build my own camera with so many well engineered options on the market. Just enjoy photography!

[@SmallSpoonBrigade]

One of the issues I have with Tony is that he's not always consistent about what he does and doesn't test. Some of the stuff, is right despite making no sense. My Canon 70-200mm f2.8L IS was never sharp on my 10D or 7D, but on my 5D mk IV, it's significantly sharper than it was on either of those bodies, even if I crop the resulting image. Without Tony, I wouldn't have consider that to be possible. But, in this case, the take home should be to apply moderate increases to the gain ahead of capturing it, knowing that depending upon the RAW format, you can probably get at least a stop or two of relatively clean signal from that point. Not to mention apply noise reduction with a much more powerful device and with smarter masking.

[@peteblazar5515]

Lower signal (without amplifying) = reduced scale (only part of ADC range will be used)?

[@DougPardee]

Right. If you use Lightroom (or whatever) to boost the exposure by 5 stops, your Raw data now goes in steps of 32 instead of steps of 1. In practice, this isn't necessarily as bad as it sounds, because of the quantum nature of the charges collected by the photodiodes and the limited capacity of those photodiodes. Raw charge data (think of it as photon counts, although a certain percentage of photons will be missed) runs maybe 15 bits worth for APS-C, and 16 bits worth for FF sensors with current technologies [those are _ballpark_ figures at best]. So if you've got a FF sensor with 14-bit Raw and native ISO 100, once you get above ISO 400 your step sizes won't be 1 any longer even with on-sensor analog amplification. [Hand-waving gets worse for dual-gain sensors.]

[@peteblazar5515]

I was thinking DR poor scene, let say 1 EV. Contrast recovery without enough of bit depth ADC ends badly.

[@ADiConsultores]

Hi!!! great insight on current ISO use... how can I establish the native ISO for a camera?? is it allways 100?

[@DaveMcKeegan]

No, it was wrong of me to suggest it's always ISO100 It's the lowest ISO available without using any expanded range

[@reyvarela9572]

As a photographer who shoots in low light I would never consider shooting in low ISO and boosting in post as the results would be notably undesirable.

[@patronusphotography]

Interesting...Your vid made me think of something: DPReview did an article recently about the Nikon Z6 banding issue, and to demonstrate they pushed a 100 ISO file up +6 EV in post. The banding is definitely present at ISO 100 pushed EV +6. However, if you look at their scene tool, and push the camera up +6 EV to 6400 ISO (which is an IN CAMERA setting), you'll notice that not only does the banding vanish, but additionally the noise levels are a bit better too. This seems to show that no, just using software to push your EV up is not the same as adjusting it in camera. The DP Review article is entitled "Nikon Z6 image quality and dynamic range impress, but not without caveats" for those that want to take a look.

[@yayitze]

If you push the image EV+6 using ColorLab instead of RGB you can go around the banding.

[@Toastmaster_5000]

The comment toward the end about shutter speed is the first thing that came to my mind. If you're putting your camera on something like aperture priority and you're taking a low-light photo without a tripod, increasing the ISO is very useful since that allows for a faster shutter. So, not only are you getting a better photo than using a low ISO+post production, you're also getting a better photo since you're not getting motion blur from unsteady hands.

[@willyricardo7009]

When you talking about noise. Did you remove noise reduction filter from lightroom? It applied by default. You need to remove that before comparing.

[@DaveMcKeegan]

Yes there is no noise reduction being applied to the image

[@robert7622]

So ISO is 95% Fake... Thanks for clearing this up...

[@martinhalmo5678]

no its not ... he made it very clear just you havent got it. Than you can say ISO is fake whatsoever even in film. because also film can be darker or brighter even the same ASA ISO or DIN (which ever measurement you use) because its dependable on developing as well as digital cameras on boosting signal. Its the same premise.

[@TonyGrant.]

...actually, ASA was written on the Kodak box but it was exactly equivalent to ISO. ISO was on Ilford boxes. In the dark days of film we spoke in ASA or ISO interchangeably according to our preference.

[@scotthullinger9955]

@Puppet Master - If people set their camera to ISO 100 or ASA 100, (That is, if an ASA setting actually existed on digital cameras, using older analogue terms here), rather than employing older analogue terms, what difference does it really make? I for one consider ASA and ISO equivalent meanings for photographers, even if they're not so equivalent for more scientifically minded people.

[@michaelclark9762]

More like it's 5% fake.

[@michaelclark9762]

@Puppet Master They weren't exactly the same to start with, but eventually the two standards organizations merged their two standards in various revisions.

[@andrepaganotti3133]

Great video ! You got all the right points and explained they in a simple, but yet, technical accurate form. Some people should really understand more about electronics before saying things about photography

[@sumeshmurali853]

Great video brother. I had these questions after I watched that video.. You cleared them

[@Metodisten]

Also cameras of same make and model can vary. They are not 100% equally due to sensors are made of organic materials, if I don’t remember wrong. Can also differ when they where made.

[@neilcamden1365]

Awesome explanation. So much clearer than most others. Great work!

[@toitarzanmoijane]

I'm not a great specialist, but I'm sure that in the 80-90's we could have had the same debat about different film makers, (Kodak, Ilford,Fuji). The different negatve films rated 100 ISO surely gave different performances in different cameras with different lens. An interesting debat though kind a sort of tempete in a glass a water... I'm glad that I don't think all about that when I take pictures. But I think that the emphasis that Tony Northrup made which is the most important for me, as that the different manufactors of digital cameras today have all adapted their own ISO standards(and that they promote as being the most senstive). 100 ISO from one camera from another and the values of ISO we can reach is really based on the manufactor's own definition of 100 ISO. In another 10 years I'm sure that we will have 100 megapixel sensors shooting at 25600 ISO on the market without 1 grain of noise in the frame, what will 100 ISO mean then? Maybe that already exists...

[@silverleafcookies]

Anthony Salema they did and changed emulsion to emulsion that’s why we bought a case and tested the film. Found the correct iso and used a Wratten filter to color correct.

[@andrewdewar8159]

If they all have different ISO100, right, how can that work with the doubling and halving ISO being equivalent to opening or closing the aperture 1 stop, or doubling or halving the exposure time ?

[@joesharples7224]

Just want to say, Dave you're the first person to explain how a digital camera process an image in a way I fully understand. Thank you very much!

[@DaveMcKeegan]

You're welcome Joe, glad I could help 😊

[@joesharples7224]

Considering going to The Photography Show, never been before, do you think it's worth it if I haven't got the money to buy any new pieces of kit haha? @@DaveMcKeegan

[@DaveMcKeegan]

Haha, still gives you a chance to try any pieces of kit you might be thinking about in the future 😊

[@villageblunder4787]

So much depends on the bit depth of the AD converter, the quality and profile of the signal amplifiers, the correction of rounding errors, the noise cancelling algorithms, etc. Technically there should be no noise introduced after the AD conversion as the values are all fixed into memory. If noise could be introduced after the AD conversion then computers wouldn't work as no values would stay the same. Most of the difference comes in the bit depth of the raw file. For a 15 bit raw file, a correctly exposed image will have values from 0 to 32767 in steps of 1. A dark image taken at low iso may only have values from 0 to 1023 in steps of 1. When the dark image is pushed 5 stops in post the values will go to 0 to 32736 but in steps of 32 making any gradations in tone (and noise) very noticeable. Try this with JPEGS and the result is even more noticeable. So Yes - Always get your ISO correct in camera. - I think!

[@rieztra]

wooow man, best explanation ever!

[@LeeRaymondCM]

I was drawing on a piece of paper trying to explain to myself like you described but I couldn't get it together good enough. Very well said.

[@sfink16]

A always like viewing Tony Northrup's video's. I don't have to agree with everything he says but I do learn when viewing because his videos make you think. He also brings out "thinking" among rival video bloggers too, judging by the recent rebuttals his videos have taken. Obviously this ISO discussion has led to multiple rebuttals yet there is nothing wrong with that. Discussion is a learning tool for many. Another topic video Tony put out recently (?) was a discussion of JPG versus Raw. That video drew the ire from at least one video blogger in froknowsphoto who took exception to the video. Again, no harm comes from opposing points of view. I don't see the point of getting so emotional in opposing points of view. YMMV

[@Lauren_C]

I was asking a rather similar question myself a couple weeks ago as to how ISO worked in digital cameras. Figured it was probably some form of amplification, though it's hard to find more precise details. Does amplification take place in the sensor, or is there some external dedicated circuit that handles that? Does the amplification scheme vary depending on device, and if so, how do smartphones handle it? I'm too obsessive...

[@DaveMcKeegan]

I think it varies from camera to camera although I believe newer sensors amplify straight off the sensor, because the AD converters are actually built into the sensor as well

[@blueckaym]

What about Sony a7III ? Several sources are saying that it's an ISO-invariant camera. Is that true?

[@darrenhall4212]

This kid loves ISO so much he bought the T Shirt ❤️

[@ThomasSchlosser]

I agree on your your take on ISO invariance. But I don‘t on your point on ISO100. ISO 100 should be same for every camera and I am sure the manufacturers try. The base ISO in my world is what the sensor captures when only A/D conversion without boosting or reducing. Some cameras have base of ISO100, some ISO200 or even ISO64. Of course these values are not exact, but not wrong by a full stop. An additional variant of. ourse is the light transmission of the lens. This is what t-stops are for as apposed to f-stops. But practically 99% of images are shot within camera light metering through the lens, so nobody cares about the actual numbers of t-stop or ISO (in the sense of a comparable, standardized number). Also a partial stop is irrelevant when using post processing.

[@WorthyUpgrades]

Very well discussed topic. Gonna stay tuned for more lmao. Finally someone that does his considering, searching, and testing. Cheers!

[@FinalLugiaGuardian]

Question for you Dave? You answered what happens to underexposed iso 100 raw photos when you bring up the exposure in post. But what happens when you over expose a raw photo with a high (around 400-1600) iso (exposing to the right) and bring down the exposure in post?

[@DaveMcKeegan]

Nothing much really since you're amplifying a signal in camera and then suppressing it afterwards As long as you don't blow out your highlights when you expose to the right then you might get more detail in the shadows, but if you blow out your highlights then you've lost that information and can't get it back in post

[@dtd2844]

I think you got caught up in the details... Though Tony did use those examples I believe he also expressed the difference was minimal. Not in those exact words... The gist was ISO was a standard in film and a ISO100 from mfg to mfg would result in very similar exposure settings without regard to camera mfg. However, digital world there is no standard. (Which completely defaults the use of ISO... Which means "equal") So though you are correct... I also believe Tony is as well. ISO in the digital camera is a completely false statement as each mfg, and even different cameras from the same mfg will require different camera settings in the same lighting condition.

[@chrisholmesphotography2456]

ISO actually is an acronym for International Organization for Standardization, iso means equal

[@dtd2844]

@@chrisholmesphotography2456 I disagree. I will concede ISO logo is used for the International Organazation of Standardization. Which initials would be IOS... ISO = Equal.

[@chrisholmesphotography2456]

@@dtd2844 ISO is in fact the acronym, you can look it up very easily. They provide standards for many things.

[@dtd2844]

@@chrisholmesphotography2456 still no... yes you look it up it will lead you to exactly what you say... except the acronym for International Organizations of Standardization would be IOS... therefore.. ISO still = equal. Quote "According to ISO, ISO is not an abbreviation. It is a word, derived from the Greek isos, meaning "equal," which is the root for the prefix iso- that occurs in a host of terms, such as isometric (of equal measure or dimensions) and isonomy (equality of laws, or of people before the law). The name ISO is used around the world to denote the organization, thus avoiding the assortment of abbreviations that would result from the translation of "International Organization for Standardization" into the different national languages of members. Whatever the country, the short form of the organization's name is always ISO." Link -> searchdatacenter.techtarget.com/definition/ISO

[@Photomeike]

Shout out to the Tony and Chelsea fanboys who are going to dislike this video because you called out their favorite KZbinr for being misleading. I had a feeling that video (Tony’s) was going to be wild by the title. But i couldn’t explain why it like you did. Salute sir

[@danwarb1]

This video itself is misleading. His test scene has a lot more light on the higher ISO side.

[@DaveMcKeegan]

Danwarb - if you're referring to the sample shots around 5:30 then there isn't more light The scene remained consistent, I just increased the ISO (the same as Tony's experiment) I was just showing strips of each file of which the higher ISO shot happened to include the light but the light was present in the 100 shot as well It's why @6:00 I compared the same part of the image for iso100 Vs iso1600 and I went with the sky rather than foreground so ambient light was guaranteed to be consistent

[@AllenFreemanMediaGuru]

I totally agree. Boosting later in post creates way more problems in the image especially in the dark areas.

[@nicolaslachance5057]

i predict this video will age well. Well done sir with the info. Im sure many photographer have been shooting for ages before knowing this bit of sensor magic, me inculding.

[@DanielGarcia-sh4xj]

I believe he was generally correct, the iso setting is fake because its based off film standard and this is digital. Like you have said the camera companies aren't held to a strict standard just an estimation so 100 might be 85 might be 105 or whatever, and that was the point. The 4 stop difference to just shoot at 100 will get you close, but you are correct it would be better to shoot at the correct exposure for the best result. I think he just mad that iso 100 should be iso 100 no matter what camera you are using and pointed this out by showing the results of different cameras. This is not a new problem, I have worked in the dark room before and NO film was exactly correct, they were close generally with the better brand films but they were Never 100% correct.

[@kxs783kms]

Best comment here!

[@ordinosaurs]

If you think iso wasn't faked by the manufacturers back in the film days, boy, I have news for you...

[@williambenson]

ISO is not fake. It only applies to the jpg. There is no ISO standard for RAW files

[@krane15]

Precision is not the issue. Tony said you can fix it later in post and that's simply not true. Granted there is some amount of latitude but its never as good as native iso.

[@williambenson]

In the film days (some of us still shoot film) we would buy our film in batches and test the first roll for iso. The same can be done for raw files which are not subject to any iso standards. No need to test jpgs though as they are already controlled by the iso standard

[@ItsFritzDaCat]

...IDK but, how about we all just forget about how any of this really matters, OR NOT, and continue taking photos with our cameras, processing them how we are and have in the past, posting and printing them and carry on like we are all normal? :) The reality of it is, none of this blaggar matters or is going to change anything in regards to the way we continue to take pictures (with the current technology) or buy cameras, is it? Not for me...

[@idontwantacallsign]

Well I don't agree that it dosent matter. I prefer less noise so it is important too shot at the right f-stoo, exposuretime and ISO.

[@ItsFritzDaCat]

@@idontwantacallsign *YAWN*...yeah ok, good for you...continue on taking photos as if you were normal... ...it went above your head...

[@duaneswaby622]

But then what would the KZbinrs do? 😂

[@Toastmaster_5000]

It does matter when there's a noticeable quality loss and time loss when taking ISO100 photos and increasing the exposure

[@carlossun9128]

Yes you can change the ISO in post, but not the shutter speed and aperture.

[@krane15]

Sometimes its not always about absolute right or wrong, but I appreciate a good counterpoint every now and then. That's the type of thing that keeps you guys on your toes, and honest. BTW, I tired fixing it post with my MK III and it didn't work. Not even close.

[@NigelDanson]

Well done! 👍

[@TheTempic]

I don’t know your channel and technical background on this topic, KZbin just recommended this video to me, but I would like to point out, that you indeed got something major wrong here. It is at 4:10. You claim, that the gain/amplification of the sensel voltages is performed before it gets through the ADC and that is NOT the case with current ISO invariant sensors. It used to be a dedicated ADC, seperate from the sensor for that. On these modern sensors, the sensel voltages go through an ADC directly on the sensor more or less directly after each sensel and that is the big thing to consider. This "short way" reduces the base noise/increases the SNR and shifts the ISO adjustment to the digital section. Most of these cameras still do have a dual native ISO or “dual-gain architecture”, so images with ISO 100 actually do have less noise and more dynamic range than at 1600. The two base ISO ranges of an A7 III are 100-500 and then 640+. You can’t change these values but the “rest” of the ISO is just a multiplication factor baked in the RAW file and this can be changed through RAW converters like Lightroom. But I’m totally with you in saying that shooting ISO 12800 and 1600 + exposure boost of the RAW file are not 100% the same. You actually do lose a little bit if dynamic range and get very slightly more noise since no Sensor is 100% invariant but the results of a modern sensor under these circumstances actually are VERY close. For my background on this: I work for one of the largest camera manufacturers (industrial, not consumer) and have a direct insight on current and upcoming sensor technology.

[@DaveMcKeegan]

Thank you for the insights I appreciate not all sensors work in that way, however Dual ISO architecture is costly to make and not all sensors are ISO invariant, so there are still cameras on the market that do work in their manner. The point I was trying to highlight is that unless you have a true ISO invariant camera, then you will have difference results from increasing exposure in camera to in post. I am going to do another video that delves more in depth into the difference ways ISO is done

[@TheTempic]

​@@DaveMcKeegan Yes, im totally with you there. Most cameras do not use this swapped ADC/ISO adjustment. It is mainly Sony who implements this in their more modern cameras but since Sony also manufactures sensors for other companys, they are not the only ones on the market. I think the main point Tony was trying to make is, that in the "real world" it doesnt really matter if you correct your image brightness +3 stops in post (if you have the right camera that is). With Canon cameras for example you won't have such a good time trying this extensively.

[@dimitris_]

I was about to write what you just said, but you already did! Nicely done! I’m also an engineer.

[@jaimeriveras]

Good, civil discussion, guys.

[@MikePageKaltenberg]

I thought it sounded a bit off (doesn't help that he can come over as a bit smug). What I don't get is is there really that much interference in camera? Good to see your tests though to prove your point.

[@user-zs1fs5ex7f]

very competently, reasonably and intellectually said. glad you saved the next generation from incorrect information and explained the basics of photography

[@JohannesLabusch]

SD cards are a hoax! Just shoot without them, and if you want your images on your computer later, use your webcam.

[@Be-Es---___]

Off course you can shoot without SD card. You know in your head what picture you took. No need to store it somewhere else.

[@Smoothblue90]

There was a man years ago who could put images from his brain onto film. He did not need the camera. But he did need the film.

[@lukestarkiller7706]

Johannes Labusch hahaha

[@Clouder77]

I'm a firm believer that getting it right in camera is always better than spending more time on the computer editing.

[@melvinch]

Unfortunately many so called "photographers" prefer the "fix-it-in-post" mentality.

[@MrPetebuster1]

Yes I agree, I really do think it's become more of cheating all you hear is pp this pp that , I'd rather spend more time taking photos than editing on a computer

[@Zeppy007]

LOL! Tell that to Ansel Adams who was the king of Dodge and Burn! You can't bring out the shadows or control the highlights without post processing! Who are you kidding :-)

[@Lauren_C]

Whatever gets you your vision, all is fair. I care not whether a photo has been heavily edited. The end result is what matters. That said, there are times where there is a very small window to get a usable shot (clouds or lighting line just right, high risk/legally ambiguous ventures, etc) where spending a lot of time getting the right shot may not be feasible. Obviously, editing can be highly invaluable here.

[@Smoothblue90]

But ... even when you get the original overall average exposure correct, you still need software to bring the image out of the RAW file ... and this often means different exposure and hue and saturation adjustments for different areas of the image.

[@tstagg]

I recently started doing photography as a business and of course I watched a million KZbin videos and I learned by trial and error that Auto ISO isn’t the way to go and once I embraced full manual, I began to see much better photos and as a “beginner”, I was a little bit confused why the “pros” were so wrong about ISO but I found this to be a few of the really good, popular channels. For me, changing the ISO and every other setting has made me a much better photographer and produced very clean and sharp photos. Thanks for the video.

[@Cali-play]

I took a class on Lightroom at Canon building in CA. As I remember my teacher said 2 stops you can change, not more.

[@ThomasO2]

Thank god. I was hoping someone would respond correctly.

[@stevem.6557]

Having Canon gear I can tell you I will be in big trouble if I underexpose 3+ stops and try to bring the exposure back in Lightroom. Recipe for disaster !! If you have trouble getting the correct exposure in a digital camera, sell your gear !! sheesh.

[@jensastrup1940]

Thank you. I was indeed confused about Tony’s video because my understanding was what you describe, ie that the analog signal from the sensor gets amplified before conversion at higher ISO’s

[@justbored3.14]

so the iso is fake then since it's different in every single make and model ? is that what it boils down to ? should it be changed to gain ?

[@DaveMcKeegan]

I don't think so as ISO is still a standardised measurements that just has a degree of tolerance, in exactly the same way as lenses with the same aperture have different exposures and likely so do shutter speeds

[@justbored3.14]

@@DaveMcKeegan i understand the example of different cameras having different shutter speeds and different lenses having different apertures i understand that but the definition for aperture and the definition for shutter is standardized. it's like mpg for gasoline you get 30 mpg on average nowadays but a while back people used to say they got 40 rods to the hogshead and that's not mpg . To summarize my point I am not saying that iso is fake or real just saying that it should be the same if it's a standard and if it can't be the same due to hardware or software differences then maybe they should call it something that will give it more of a variable like gain .

[@frederic-xavierdubois8289]

Hello, I'm in sensor manufacture company and you cannot be more right !

[@JonPais]

Tony’s right. 1) On most digital cameras, ISO is just digital gain. 2) And one reason the pictures lifted in post are noisier is because the camera is applying some processing even to RAW files. 3) He’s also right about ISOs being rather arbitrary.

[@melvinch]

He has more wrongs than right, making him the ideal false prophet of photography.

[@RichFreeman]

From what I've read most Canon cameras are not ISO invariant. I did my own test on my 6Dii and there was way more noise on a lower ISO with the same shutter and aperture when conditions were dark. Maybe his statement is true for some, many, or maybe even most cameras. However, it seems like it isn't true for most Canon models and that isn't exactly a no name manufacturer.

[@DaveMcKeegan]

Except arguably ISO isn't digital gain because it's the analogue signal that is being increased. ISO in cameras is like audio recorders, it's the preamps that boost the audio before it's saved, not just turning up the digital volume later

[@aGabay]

Even if the signal boost is a digital one - it performs differently than the lightroom/photshop/whatever algorithm performs like, thus giving different results. The in camera boost is "tuned" to the specific sensor and processor.

[@luttekikker]

@@DaveMcKeegan So, ISO values are equal to the amount of recording level on recorders? Or is it equivalent to the "High Gain" setting most (hand) wave recorders have. I have the Roland R-05 and I use always the Hi gain setting instead of turning it off and boost the sound levels in post during editting for example. Is it also better to record in the lowest recording level setting (in normal) and boost in in post anyway in order to get the cleanest sound since High gain settings is only a boosted analog signal (real world sounds hitting the microphone and gets amplified before getting it transformed to a digital signal)?

[@atamanphotography]

you both have a point (tony and you). but i dont think there could be a much difference between boosting the singnal before and after a.d. i think the cameras put in noise reduction even if you disable this option

[@DaveMcKeegan]

The difference is, as you pass a signal round you introduce more noise, if you amplify the signal later then you amplify the noise as well. As a basic example if you get 4db of light signal (not the correct units) and you're going to boost it by 2 stops up to 16db, if the circuit introduces 1db of noise in the process then boosting the signal straight away will give you 16:1 signal to noise, however if you boost it afterwards you end up also boosting the noise by 2 stops so you'll end up with only a 4:1 ratio

[@MrNeilRoberts]

We’ve come a long way since I was trying to thread b&w 35mm film onto the reel of the developing canister in my mum’s airing cupboard / come dark room lol 😂 😂

[@GeorgePop]

The most important point is for new photographers to understand that this ISO doesn't exist nonsense is not true, it does exist since every camera has a number for it. Of course, it's not the same as the film days ISO since back then each film company had to send their film to get standardized and thus called ISO for each roll of film. These days camera companies make their own sensor or buy it from another company so there is no standardized correct ISO number for any of the cameras. However for the photographer that ISO number still means what it meant in the film days, if you shoot at higher ISO than the minimum one as per your camera's sensor you will increase the potential for noise in your photos due to the sensor processing the information by boosting the signal to get more light. It's important to not teach amateur photographers that ISO in digital cameras is meaningless, that they can take a photo at any ISO and it can be fixed in post or that all camera manufacturers are lying to the consumers and they can buy any camera and then they will be able to take the same shoot and make it look exactly the same, cause hey ISO doesn't matter.

[@barmalini]

As someone who have actually studied electronics at the university, I am admiring how clearly and concisely you have explained where exactly Tony has made a mistake. Well done, Dave!

[@SmallSpoonBrigade]

I agree. The conclusion here should probably be that in most cases, a modest boost in the ISO is prudent knowing that with RAW formats, you'll have extra bits to work with and much more powerful hardware to engage in noise reduction. A 10bit RAW file has roughly 4x the values possible to work with and a 12 bit has 16x as many, which is roughly 2 to 4 stops worth of data. Underdoing the ISO slightly by a stop or two is probably not unreasonable if it allows you to use the ISO that your camera produces the least amount of noise with. Part of the issue with both of these videos is that the lowest noise on the sensor isn't necessarily at the lowest ISO, it may be a couple settings up from the bottom, in which case, you get a bit of free lunch by just using that if you can and then using that as your base point for further work. Boosting that by a few stops in post production may well give you the best quality you're going to get.

[@koolkutz7]

Good one Dave, nice clear, concise explanation. In a basic sort of way, I kinda think of ISO in digital cameras as a bit like gain on an amp (e.g. if I plug my electric guitar into my amp and turn up the gain/volume it is louder but much more distorted (ala noise).

[@ps.photos]

this was very clear.TNX! btw? did you meet Tony after this recording? :-)

[@paulwood6729]

Tony's point about ISO 100 is that it isn't set to a standard level. ISO 100 doesn't give consistent results across manufacturers or even cameras. You've tackled him on a different point.

[@DaveMcKeegan]

Yes, however film didn't give truly consistent results either, it would vary from brand to brand as well

[@primefotoNL]

@@DaveMcKeegan I wonder how big the difference in ISO was with film compared with the differences in ISO within digital camera's today. If the difference in film is a lot smaller then digital could have been a standard within tolerances. Wondering when is something consistent. What makes the difference between consistent en not being consistent. Where to draw the line. In my opinion film was consistent enough, within manufacturing tolerance, to be able to say that there was a standard. ISO was the parameter that told you how long to develop the film. It must have been close enough to give good consistent results. Digital might be off a lot more than film ever was.

[@williamneuman7783]

@@primefotoNL Yes, back in the day, film had to meet a certain standard within allowable tolerances so diferent brands of film were very close. Digital camera have a wider variance in that standard so ISO numbers aren't as closely accurate between brands as film was. I was shooting film from the 70's till the 2000's.

[@MrBlackblacker]

agree. ISO100 in different brands have different approach to the ISO100. It is not standardized anymore. tsk tsk tsk! i could not even finish this guy's vid.

[@osliverpool]

@@DaveMcKeegan Not just from brand to brand, but also from developer to developer - the same film can have significantly different actual ISO when developed in, say, D76 and Rodinal

[@keiyumamiya8920]

Nice tee shirt for the video. I know you always wear it for videos but you know.

[@Redonepunch]

How is f stop theoretical when it’s simply the diameter of the iris in relation to the focal length and is not meant to represent light transmission?

[@DaveMcKeegan]

Because in theory, 2 lenses with the same aperture should create the same exposure

[@tomhath8413]

The main argument here seems to be that shooting at lower ISO and boosting in post-processing results in more noise. What I don't know (but suspect) is that the camera is doing some denoise processing at higher ISO. Does anyone know if that's true?