Native and Base ISO | Ask David Bergman

[@dennispeterson3691]

Great explanation! And a great example showing noise can be fixed, but motion blur cannot. You are always worth watching!

[@viictorgarza]

Best explanation on KZbin so far... I've been searching for some clear information about this with no success. This is just perfect, it gets to the technical point wich is essential to understand how our cameras work. Once understanding the geeky part, the rest is just easy to learn.

[@rickfarber4243]

This was a bit more technical than usual, but super helpful and clear. Thanks.

[@GlasscityAl]

Thank you I definitely wanted to get that understanding of how that worked and why its important

[@AdrianBacon]

In Canon cameras (what I'm most familiar with) Native/Base ISO is where there is no additional analog gain added or removed before the ADC, meaning the voltages/gain that are there are the minimum required in order to convert the sensor signal to digital with the minimum amount of noise and error for that ISO setting. Extended ISOs are digital gain adjustments done after the ADC. For example, on Canon cameras that have ISO 50 available as a low extended ISO, the analog gain is exactly the same as when ISO 100 is used, the camera simply lets twice as much light hit the sensor (when not in manual mode), then pulls the exposure down by one stop when rendering the raw file. You can use tools like raw digger to inspect the raw ADC values and compare them between those two settings. If you're in manual mode and take a photo at ISO 100, then take the same photo with the same shutter and aperture settings but with the ISO set to 50, the RAW ADC values are actually the same between the two. The camera digitally pulls the exposure down by a stop when rendering the raw values. This gives significantly less noise in the shadows, but comes at the expense of one stop less highlight overhead because you're basically overexposing ISO 100 by a stop.

[@boloki72]

I did not know that there's an analog gain, sensors are digital and gain occurs in the amplifier circuit for the sensor output of the camera.

[@MrDunk66]

@@boloki72 sensors might have some “digital” characteristics in that they are measuring discrete photons, but the voltage output signals are analogue (voltage rises continuously with exposure until the shutter closes, unless the sensors photosite gets saturated before the exposure is completed - blinkies!) otherwise the circuit would not have an ADC.

[@ralfg9194]

From what I understand of the signal processing chain (CMOS diode capacity, diode voltage, analog amplification of the diode voltage which is the only influence point of the "ISO" choice, analog/digital conversion, digital pixel information) I believe that your understanding of the native or base ISO is absolutely correct. Kind regards from Germany!

[@brad_in_yyc]

Super nerdy. I love it. Thanks David!

[@MrGeister]

Thank you so much for the excellent, clear explanation.

[@phynx2006]

ISO smart now, thanks Dave 👍😎

[@HeeraShahid]

nice short explanation david I always love to watch your show like the way you explain and love to watch your smiley expression give me every time a positive energy maybe you know or not everyone doesn't have this it's a gift of God (it seems natural)

[@snitzoid]

Changing the ISO can have a massive impact on dynamic range. For example shooting with an Sony A7r V at ISO 100 provides almost three stops more dynamic range than at ISO 800. That's a big deal. Just about all modern DSLR and Mirrorless camera sensors show similar impacts on the dynamic range as ISO increases. As for digital noise, new noise reduction software (AI option in Lightroom) and DXO's noise reduction software can drastically reduce noise without sacrificing sharpness.

[@tedk2814]

You explained this so well, even I understood! I didn't know about the dual native iso mostly in video, now I do. Shooting sports like high school night foot ball games or in poorly lit gyms will quickly teach you about iso. My typical iso with a D5 and 400 2.8 was from 10,000 to 16,000 iso shooting at 1/1250. Honestly, if I filled the frame, and didn't have to crop, the images were very useable. I think my Z9 does as well, time will tell. I don't have a proper education in photography so I've learned from Adorama presenters like you that did learn from the ground up for a career. Thanks so much David, I wish you happy holidays from Sebastian, Fl, the home of the $9.00 haircut. ( $12.00 now )

[@DavidBergmanPhoto]

Inflation! :)

[@user-mi5he4wt5n]

😊

[@philiphatton]

The subject of ISO invariance would be an interesting follow-up to this

[@mrstudios010]

Yes, but then Canon users might get scared when they see the saw chart of invariance vs Nikon's steady line.

[@AliasJimWirth]

Thank you. It has taken what seems like forever to get an answer to this question. Now I have it; cross another one off. Have a nice Thanksgiving, all.

[@jpdj2715]

Very well explained, David. Two additions/details. The ISO institute defined "ISO" but does not prescribe "correct exposure". This means that ISO relative to what you deem correct exposure can differ between cameras (brands). Second, as you explain amplification in the sensor, that is excellent conceptually, but the potential to alter voltage as a way to amplify a photosite is limited and in that sense, it cannot go as far as the ISO range our cameras have - by far. Many mirrorless cameras now have sensors with two fixed amplification levels. My Nikon Z 7ii starts at 64 ISO in its first amplification level and when I raise the ISO level, this causes some noise to appear increasingly until near ISO 400. Some specialist website exists where you can find the noise plots s function of ISO. In the case of my camera, at 400 ISO, the noise level drops back to the level of 64 again and from there goes up again. When we see noise in our images, we however have to be at guard because it may just be failed raw processing. And then when we run our image through, say Topaz DeNoise AI or DxO PureRAW the noise disappears (or not) so we know it is one or the other.

[@rapideyephotography9782]

Great explanation. Thanks David.

[@prosunsport1]

The noise is a result of the magnetic field interference (electrical noise )between each pixel circuit when voltage is increased to increase the sensitivity of sensor at higher ISO

[@paulhills1967]

Great explanation

[@organicrobot4710]

Great information...nice work! 👍

[@djjrodnyc]

Good info!

[@badi_music]

When it comes to the crucial and perfect moment to shoot the action, it's better to have a well exposed photo with all the noise that can be in the world, than the frustration of messing the action moment and getting a ruined underexposed photo due to the mindset of "low ISO." let your Iso free most of the time.

[@randalalansmith9883]

Maybe some day there will be a camera that saves analogue raw that's exportable. So you can choose the ISO later.

[@Albertoabrian]

So what is Base ISO for a6700 In Photo mode, I found that ISO 100 is just above the “up line bottom line” ISO So 100 is base ISO? But then I found ISO 3200 just below the “up line and bottom line” ISO So does A6700 have dual ISO??

[@HR-wd6cw]

I would suggest for those curious as to how well their cameras behave at externded ISOs is to do some tests. I just did a test on the low-end (so ISO 31, 40, and 50, and then my camera's native ISO 64 -- camera is a Nikon Z7 by the way and most cameras have a base ISO of 100). So what I found does seem to support what is claimed here: there is a tad bit more details in the shadows at the extended ISO (in my case I found the most shadow retention at ISO 31 or 32, over ISO 64). As far as highlights go, they are about the same (the base ISO 64 may actually have slight highlight advantage at least in my camera, but as long as you don't blow the highlights, you should be fine). Tony Northup has a video about this and I think that while it is true that using extended ISOs (lower ones, not the high-extended) are beneficial, it may vary. For example in my case, the differences between ISO 31-32 and ISO 64 were not as great as say between a camera with a native ISO of 100 and an extended low ISO of 50. For me I may play around with ISO 32 (extened) but I may no push it too much, as I like to stick to native ISOs, but it is good to know that with a modern camera (one made in the last say 5 years or so) using extended low-ISOs is fine in most cases. I wouldn't necessarily do this on an older camera say one from 8-10 years ago, as I felt those maybe didn't help as much and in some cases, could lead to more issues than it's worth, but with a modern camera, I think bumping exposure down 1/3 or 2/3 of a stop below native ISO is fine and may yield some bneefits, especaily in the shadows areas. I don't think it does as much in terms of noise (as I found from PhotonsToPhotos for my camera, where the noise ration is relatively low on my camera anyway from ISO 32 to about ISO 64 and any diffferences are not really visible in terms of noise unless you're zoomed into maybe 800% or more and even so, it may be hard to see the differences).

[@L.Spencer]

I think my camera is considered a basic one, Canon Rebel t6, so the ISO noise at 6400 seems like a lot. So whether this applies depends on what camera we have. I appreciate the explanations, I hadn't heard of much of this. :)

[@andrewelder2739]

Great stuff!! But the one question you didn't answer is how to find out what the base ISO is for various cameras! I swear I can't find that anywhere 😜

[@evocati6523]

5:13

[@billravens8136]

No, the exposure triangle is aperture, shutter speed, and available light. ISO is not part of the triangle. Iso is either metadata, or it's artificial electronic boost.

[@felixrodriguez782]

so using high end lens give one better image control in low light with a less issue of noise in the image

[@PizzlesTechTime]

The Canon R5C has two base ISOs in log and raw and two base ISOs in natural picture profiles.

[@garyrowe58]

I believe that at the different 'base' isos, the Dr is different - that's what i want to learn about and know

[@cesaraugustomargato7211]

And the guy hasn’t explanei that! Native is different from base ISO!!!!

[@thomastuorto9929]

I was getting ready to go to ask DB about the dual iso thing so, thank you. I haven't seen (or noticed) any camera manufactures list Dual ISO in their specs. If this true, it would be nice if they did.

[@NathanDowdyMedia]

Blackmagic 6k pro has a dual ISO, but while it will take stills, it's primarily a film camera. I have it, and can say that the ability to have two native ISOs is a great feature.

[@joshuahutchinson2444]

Lumix s5ii 😅

[@godancs2]

I know its stupid question but does phone's camera has native iso?

[@johnclay7644]

informative 8mins.

[@mtmccornack]

I have a Sony fx3 with dual ISO (12,800 & 640 I think?) however my question is.... when i switch over to still mode, do I assume that 640 is the still the lowest clean ISO and i should think about the exposure triad from that metric, or should choose 100 ISO like cameras from my past and work my exposure triangle from there? youtubers always seem to prioritize film explanations over stills even when a camera can do both?

[@jamescaldwell5]

I have a Sigma FPL, with an ISO that can go down to 100 in standard mode, is there any way to tell if this is indeed the optimal native iso?

[@BlueBass2]

what are some cameras with dual base ISO?

[@heyroys]

Noice😁

[@yangho8]

there is no real iso in digital camera. aperture and shutter speed consider how many light reach the sensor. the A2D decide how low they can seperate signal vs noise floor. whatever they design is natve iso. after that they apply digital amplifier which clip the native iso signal (crush black or white). if you shoot raw, they record in native iso signal and apply digital iso in post. dual iso actually two a2d for low and high gain signal; you must manually choose by dial iso number. Interesting GH6 record the 2 a2d signal at same time and combine to have theorically better image.

[@georgemcgnarly3144]

Does this mean I should throw away my 7 bricks of Pan-X film?

[@SakkiDuran]

He got so many things wrong...

[@mcccccccccc]

Like what?

[@rogermanning4353]

Thanks for saying EYE-so insted of I-S-O . . . one is it's name . . . the other is not. Cheers!

[@evocati6523]

It's not a word it's an acronym. Do you say U S A or oosa?

[@JohnMacLeanPhotography]

Roger was film speed Ahh-sa? I didn't think so! It's A.S.A.

[@rogermanning4353]

@@evocati6523 From the ISO home page . . . Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French for Organisation internationale de normalisation), our founders decided to give it the short form ISO. ISO is derived from the Greek 'isos', meaning equal. Whatever the country, whatever the language, we are always ISO.

[@rogermanning4353]

@@JohnMacLeanPhotography Nope . . . . ASA was indeed and acronymn. Again, from the ISO page . . . Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French for Organisation internationale de normalisation), our founders decided to give it the short form ISO. ISO is derived from the Greek 'isos', meaning equal. Whatever the country, whatever the language, we are always ISO.

[@rickfensch]

Meh, not the best explanation. Some things could still be explained better. At least you didn’t say that higher ISO’s make the sensor more sensitive. I think the explanation should be more technical. At least, bring in an expert that will choose all the correct words to explain it correctly. This is a important issue these days that many photographers are now starting to care about. And there’s still so much miss information out there that doesn’t clarify what the sensor is really doing.

[@leestrickland]

That depth of explanation is not intended for the target audience.

[@wayneberry3453]

A important issue? Lol