Understanding Dual Gain ISO on the Nikon Z6 III and other cameras

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  • @testcams
    @testcams  4 місяці тому +22

    One point I forgot to include in the exposure strategy section is how raw shooters don't ever really need to use the intermediate ISOs between ISO 100 and 800, or the ISOs after 800, since those ISOs provide only modest benefit over ISO 100 or 800 in terms of noise, and actually are a detriment to dynamic range since they amplify the image data at the time of shooting and limit your options to selectively boost the exposure in post while still retaining your highlights. In short, shoot at either ISO 100 or 800, even if that results in a photo that looks underexposed in the camera, since you can normalize the exposure in post and retain the maximum dynamic range. You'll want to measure this for your own shooting because while the improvement in noise shooting at the indicated nominal ISO like ISO 6400 vs "underexposing" at ISO 800 is modest, that improvement goes up as you go further into underexposed territory. For jpeg and video shooters, you'll generally want to continue using the intermediate ISOs because those formats have limited bit depths, which limits how much you can boost the exposure in post before running into posterization and clipping issues.
    Also, if you'd like to find the Dual Gain ISO of any camera without doing the work yourself you can use Bill Claff's site. Click on a camera on his PDR measurement page. The Dual Gain ISO will be the ISO where there's a noticeable jump in the measured PDR on the graph. Here's the link: www.photonstophotos.net/Charts/PDR.htm

    • @xchump
      @xchump 4 місяці тому +1

      Please bear with my noob questions.....so are you saying that since I shoot Raw, I would basically never benefit from going over ISO 800? Even if the pictures are underexposed, I should be able to fix that in post, and it will yield better IQ results than going for a higher ISO setting at the time of shooting?

    • @boblozano
      @boblozano 4 місяці тому

      Will experiment with this. Will be interesting to see where /if focusing / composition degradation (from the apparently lower light that the photographer uses to make decisions) costs more than the improved headroom gained (pun intended) by avoiding the gap isos (base 1 > gap iso < base 2).
      That leads to another change that would probably require firmware, in which the actual raw is encoded only with one of the two base isos (or the dual-gain), but the image displayed for the photographer responds precisely to the `apparent` iso selected, either manually or auto.

    • @zakiradi450
      @zakiradi450 4 місяці тому

      This is not true. Plain stupid to be honest.

    • @boblozano
      @boblozano 4 місяці тому

      @@zakiradi450 ad hominem is not an argument. Evidence would be useful.

    • @guate6
      @guate6 4 місяці тому

      What are remarkably interesting video. Does this mean that if this option comes to full frame cameras camera would it have to be a hardware change or can it be made by firmware?

  • @branimirteodorovic2297
    @branimirteodorovic2297 4 місяці тому +10

    Finally somebody on UA-cam who actually understands how technology works

  • @sharkcookie.YouTube
    @sharkcookie.YouTube 4 місяці тому +11

    The best explanation about this topic I have seen! That's so much.

  • @kuau714
    @kuau714 4 місяці тому +11

    This video is a MUST see for every photographer

  • @avtoVELOoperator
    @avtoVELOoperator 15 днів тому +1

    Genious and simple video.. simple for watching, complicated to make. THANK You)))

  • @shadow479
    @shadow479 4 місяці тому +7

    This is mind boggling, it breaks the logic of the traditional linear direct correlation of "higher iso = more noise".
    Great job, sir. Thank you for this test and revelation!

  • @josephvalentinephoto
    @josephvalentinephoto Місяць тому

    Best explanation of dual gain ISO I have seen! Bravo and thank you!

  • @guyyowell8547
    @guyyowell8547 4 місяці тому +4

    This is the best explanation of noise and gain as it relates to exposure I’ve ever heard. This is very helpful. It’s interesting that the gain for the Z8 (and probably the Z9) occurs at ISO 500. This is likely due to the higher pixel count, and the fact the pixels are more tightly packed together.

  • @solardungeon
    @solardungeon 4 місяці тому +8

    Wow!! this is the most informative video on Z6iii noise

  • @MarkLewis-l3f
    @MarkLewis-l3f 4 місяці тому +2

    One of the most significant factors I look at in determining whether I need to subscribe to a photography channel on UA-cam is based on evaluating the content with an eye to the need to watch something multiple times in order to be sure I have a sold grasp of it. In other words, I'm asking two questions; 1) Is this really necessary information?, & 2) Do I need to go back over this & keep referencing it like a study guide in order to make sure I can retain it? The answer in this case is clearly yes to both questions. Kudos for this work.

  • @AmadeuszAndrzejewski
    @AmadeuszAndrzejewski 4 місяці тому +1

    You have a great talent for explaining technical things in a simple and understandable maner

  • @wanderlust0120
    @wanderlust0120 4 місяці тому +5

    0% intro
    0% outro
    100% ISO
    Subscribed

  • @johnhernlund539
    @johnhernlund539 4 місяці тому

    Excellent video, great explanations. I will try this same test with my other cameras, to see how they turn out.

  • @sharkcookie.YouTube
    @sharkcookie.YouTube 4 місяці тому

    I'm patiently waiting for you to post something about shooting video, especially when. It comes to shooting Nraw. I have avoided N-log because it's base ISO is 800 which requires me to use a ridiculously short shutter speed when I'm shooting outside.

  • @rbob4931
    @rbob4931 4 місяці тому +1

    Fascinating to say the least.
    Well done!!!

  • @chantaljacques7664
    @chantaljacques7664 4 місяці тому

    Thank you for sharing this on FM. Great information!!!

  • @boblozano
    @boblozano 4 місяці тому

    Really superb engineering analysis and testing. Keep it up.

  • @jakilahmoulien9070
    @jakilahmoulien9070 4 місяці тому +2

    this video is gold

  • @sagardigitallab
    @sagardigitallab 4 місяці тому

    Superb !
    'The best video ' todate-- explaining ISO and Noise relation

  • @RejeRush
    @RejeRush 4 місяці тому +2

    Would love to see a video breakdown of the z6iii vs the z8 in dynamic range, iso performance and how each respective dual gain iso affects an image.

  • @grahamland7703
    @grahamland7703 4 місяці тому +1

    Explains such a lot, had gravitated to shooting at iso 800 as my preferred setting for light challenging situations, very resilient to being pushed. Results at higher iso's tremendously mixed, if exposure slightly out.... But sadly iso 800 has it's limits when you have to shoot movement. Many thanks for lighting my darkness!

    • @kjltube
      @kjltube 4 місяці тому

      But if you set your evf to NOT show the actual exposure brightness (instead a brightness that allows you to compose), and shoot manual iso 800, and the appropriate manual shutter speed you need to freeze movement then you should be happy. Unless perhaps if your scene is super dark?

  • @Hrishi1970
    @Hrishi1970 4 місяці тому

    Wow. Interesting video. Thanks!

  • @JohnVijayRaj
    @JohnVijayRaj 4 місяці тому

    Awesome explanation thank you

  • @raudelravelo1169
    @raudelravelo1169 4 місяці тому +1

    Awesome video. Keep it up!

  • @robertLuxama
    @robertLuxama 4 місяці тому

    That sounds really interesting this software you'v created!! Will it be in sale? Is it for video?

  • @dominiclester3232
    @dominiclester3232 4 місяці тому

    A great video, thank you! Will you be selling or sharing your software sometime soon, please?

  • @Sebas-sg1kj
    @Sebas-sg1kj 4 місяці тому

    What an amazing video! Question: if i need fast shutter speed to freeze movement, should i go for iso 800 instead of using values from 200 to 650 for example?

    • @testcams
      @testcams  4 місяці тому +3

      If you can shoot at ISO 800 without having to increase your shutter speed further to prevent overexposure then you definitely want to use ISO 800 whenever possible.

  • @rsmolkin
    @rsmolkin 4 місяці тому +1

    Do you know if Z6 ii has a dual iso as well?

    • @testcams
      @testcams  4 місяці тому +2

      It does, as does the Z6. All three generations' dual ISO is at 800.

  • @aldolega
    @aldolega 4 місяці тому +1

    Arri and some Canon cinema cameras use dual-gain systems like you describe at the end of the video. The newest Arri sensor reaches 17 stops of DR and it isn't even full-frame!

    • @Bayonet1809
      @Bayonet1809 4 місяці тому

      Yes, they use a simultaneous read-out, which is currently not available in stills cameras.

    • @Wildridefilms
      @Wildridefilms 4 місяці тому +1

      @@Bayonet1809 it is available on the G9ii, GH6 and GH7. Though the GH6 only activates it at ISO 800. The other 2 do it from ISO 100 and match the DR of 14 bit readout APSC and sit between 12 bit APSC and 12 bit FF.

    • @Bayonet1809
      @Bayonet1809 4 місяці тому

      @@Wildridefilms I am unfamiliar with the internal workings of those Panasonic cameras, but there appear to be no real benefit to whatever they apparently do. Photons to Photos shows the maximum dynamic range of the G9II to be effectively the same as the older G9 (PDR ~10), while the APS-C Sony A6700 manages a PDR of almost 11. That evidence suggests that there is still a significant gap to APS-C, contrary to your claims.

    • @Wildridefilms
      @Wildridefilms 4 місяці тому +1

      @@Bayonet1809 Take a look at cine D or Gerald undone. In video, they sit right in between 12 bit APSC and 12 bit Full frame.
      I don't know how Photons to photos do their tests, but if it says that the G9 and G9ii are even close in max DR, they're very wrong. There's a huge difference between them. The G9ii is at least 1 stop better, closer to 1.5 stops better than the G9.

    • @Bayonet1809
      @Bayonet1809 4 місяці тому

      @@Wildridefilms Oh, you are referring to video. Well that explains it. I was talking about the feature not being available for stills.

  • @barrymackichan7074
    @barrymackichan7074 4 місяці тому

    One other point. A lot of photographers shoot “manual mode” with auto iso. The amount of light hitting the sensor is independent of the iso, so (assuming you don’t cross the line between the dual iso domains) auto bracketing will have no affect on the raw files other than changing iso number, just a number, that’s embedded in it. Similarly, taking exposures for HDR, would give multiple raw files that are essentially identical. For these methods to work, you need to set the ISO to be constant and change the exposures in a way that affects the amount of light going to the sensor - either aperture or shutter speed priority or manual. Am I correct?

    • @testcams
      @testcams  4 місяці тому

      Agreed, there's not much benefit in AE bracketing with Auto ISO, unless the bracket pushed one of the Auto ISO exposures into a Dual Gain ISO, and the software used to create the merged exposure accounted for using the lower EVs of that bracket. But even then if you're bracketing you might as well bracket the physical exposure (shutter speed/aperture) rather than just the ISO.

  • @Ben_Stewart
    @Ben_Stewart 4 місяці тому

    Variable ADU is a problem with newer CMOS sensors. In Astrophotography sometimes it is better to just expose with a higher gain setting rather than little to no gain.

  • @SolidMGSnake
    @SolidMGSnake 2 місяці тому

    Interesting

  • @vivalasvegas702
    @vivalasvegas702 4 місяці тому

    By July 17th, you’re going to have to explain Triple Gain ISO,🤞🤞🤞

  • @nigerian-nightmare
    @nigerian-nightmare 4 місяці тому +1

    Can this be applied to Canon cameras or Panasonic, or is each brand different?

    • @Bayonet1809
      @Bayonet1809 4 місяці тому +1

      Panasonic yes, Canon no. Canon uses their own different sensors.

  • @grindpolicy
    @grindpolicy 3 місяці тому

    does shooting in one of the internal raw modes change the gain levels like how the nlog does?

    • @testcams
      @testcams  3 місяці тому +1

      On the Z6 III you can shoot internal raw with either SDR or NLOG. In SDR the dual-gain ISO is at 800. For N-Log it's 3200. So the same as for the Z6 III's Long GOP video modes.

  • @b34k97
    @b34k97 4 місяці тому

    Alright, I feel like you've buried the lede here with that very short segment on Dual ISO readout simulation at the end. I'm really curious now, as I think your test shot output looks really good! Much more natural than some HDR shot's I've done in LR previously. I have a few follow up questions here:
    How does this differ from an HDR Merge in Photoshop or Lightroom?
    Is your simulation software open source and/or available on GitHub somewhere?
    Does the software act on (and produce) a RAW (nef) file, or some other file types?

    • @testcams
      @testcams  4 місяці тому +2

      I have an open-source project for all my raw-based tools at github.com/horshack-dpreview/OctaveRawTools. I haven't added this file yet. It's kind of hacked together at the moment and would need more work to make it usable across all cameras.
      Keep in mind the dual ISO readout simulation requires shooting two exposures and merging them together into a single raw, whereas a future, sensor-based implementation would accomplish this in a single exposure. Since you have to shoot two exposures you're better off using exposure bracketing, as it will provide noise improvement across a wider tonal range than the EV-grafting of my dual ISO readout simulation.

    • @b34k97
      @b34k97 4 місяці тому

      @@testcams Oh cool, thanks for the repo link! Yeah, it makes sense that the real power here would be getting this output without needing to take multiple exposures.
      I really did like how naturally your program seemed to stitch the two exposures together though... better than I've been able to do with exposure bracketing (though I'm still a beginner at this type of editing, so probably not the gold standard to go by).

    • @barrymackichan7074
      @barrymackichan7074 4 місяці тому

      It seems to me that the constraints are the resolution of the luminance measure at the shadow end (how close can two intensities be and still produce pixels with different values?) and the ‘overflow’ at the high end that leads to blown out highlights. The second problem seems to me to totally solvable by increasing the number of bits available in a pixel because the constraint here isn’t in the sensor hardware, but simply having enough bits to store the result of a computation. It should cause no problem for post-processing software (although the algorithms will need tweaking). I would think that a logarithmic scale would also fix this, but I don’t know much about them - yet. I have another question - in this two stage process with an analog step on the sensor (?) followed by digital multiplication essentially by the ISO, is one inherently better, provided enough bits are available to avoid overflow?

  • @iammandeeppunian
    @iammandeeppunian 3 місяці тому

    Can someone tell me plzz when we have dual iso value like 800-3200 so it mean we can use one of them ? Not between ?

  • @mihan2d
    @mihan2d 4 місяці тому

    I have a question, is the statement true that Z6 mk. 3 would have worse low light performance than a mk. 2 due to its partially stacked sensor due to the sensor design being more complex and therefore the amount of light on each pixel being more limited than a similar "plain" 24 MP BSI 35 mm sensor?

    • @RejeRush
      @RejeRush 4 місяці тому

      He did tests between the high ISO and dynamic range capabilities of both the z6iii and z6ii in previous videos. Great videos!

  • @RejeRush
    @RejeRush 4 місяці тому

    Question: I shoot weddings and faced with low light conditions that would normally have me going higher than ISO 800. Are you saying I should just keep my ISO at 800 even if the photo "look" underexposed?

    • @Bayonet1809
      @Bayonet1809 4 місяці тому +1

      Yes, the only issue is that unfortunately mirrorless focus systems rely on a bright live-view image for their calculations, so if you are struggling for focus you should increase ISO to make the image brighter.

    • @RejeRush
      @RejeRush 4 місяці тому

      @@Bayonet1809Thanks. Very interesting

  • @maldeojocomunicaciones8427
    @maldeojocomunicaciones8427 4 місяці тому

    So, in the case of video, the native Iso of 6400 only applies when using N-log and reverts to 800 when using any other profile?

    • @testcams
      @testcams  4 місяці тому

      Yes, the indicated vs sensor ISO discrepancy doesn't apply to any of the SDR-based profiles. I forgot to mention HLG in my video, which uses a sensor ISO that's 2EV below the indicated vs 3EV below indicated for N-Log, which means HLG ISO 400 is sensor ISO 100 and HLG ISO 3200 is sensor ISO 800.

  • @tinger20
    @tinger20 4 місяці тому

    Am I understanding the chart correctly, that the 150mp Phase1 has 7 steps?

    • @Bayonet1809
      @Bayonet1809 4 місяці тому

      No, it only shows one additional gain level at ISO 400. The other steps in the graph just indicate that Phase skimped on their ADC firmware. Which makes sense since most of their users are not shooting above ISO 100 anyway.

  • @cameraprepper7938
    @cameraprepper7938 4 місяці тому

    If you want the highest possible dynamic range in a photo image, then use the base ISO !!!

  • @boblozano
    @boblozano 4 місяці тому

    www.youtube.com/@testcams any idea whether the z8/z9 or z6iii sensors have the ability to change the gain strategy via firmware, or is it hard-encoded in silicon?

    • @testcams
      @testcams  4 місяці тому

      Good question. I'm guessing the dual gain switch is hard-coded in silicon to the ISO value, which firmware sets in the hardware interface/register, so it's under firmware control but not control that's independent of the ISO.

  • @ropeyarn
    @ropeyarn 3 місяці тому

    So as I understand it, camera manufacturers have been relying on bit depth and software to emulate gain all these years, without any of the camera influencers telling us, and we are left to wonder why our still cameras suck.

  • @danielvilliers612
    @danielvilliers612 4 місяці тому +4

    Why use adobe software to do your test. It is known that at least at the start, Adobe induced much more noise to the Z9 images than Capture one. Why at least not use Nikon own free Nx Studio or Capture One, to get a more rounded example.

  • @BobN54
    @BobN54 4 місяці тому

    Sorry to say, your explanation of dual gain is very confused and muddled. You've tried to make sense of the term 'conversion gain' and been confounded that this name is actually a misnomer - it's a conversion factor - not a gain at all. This is compounded by another misunderstanding, that 'gain' is applied to exposure. This is just incorrect. The exposure is immutable once the shutter is closed. It signifies an amount of light, and nothing that is done electronically or computationally results in the gain of light.

    • @testcams
      @testcams  4 місяці тому

      Thanks for the feedback Bob. I followed Aptina's lead on using "conversion gain", which is how they termed the technique in the whitepaper discussing their invention of the technology. I agree with your general strict use of the word exposure, although its colloquial usage won out in my choice to use it in parts for the intended audience. I drew a pretty clear arc between that colloquial usage and the stricter form of physical light exposure (aperture, shutter) at important parts of the video, so I'm on board with shifting the usage to the stricter form, although I'm sure we probably differ on how to approach and introduce that shift to others.

    • @BobN54
      @BobN54 4 місяці тому

      @@testcams The term 'conversion gain' is what the industry uses, but as I said the name is misleading. If you understand it as a 'gain' you'll go wrong. It's a conversion factor and in particular dictates the equivalence between photon and electronic noise. So, if a high conversion gain is used an ADC producing a given amount of electronic noise appears to be less noisy than it would with a low CG. But a high CG limits the amount of charge that can be read from the pixel. Dual CG allows low CG to give a lot of charge for low ISOs and a high CG for low read noise at high ISOs.
      Charge is directly proportional to exposure, so inversely proportional to ISO. On exposure, I know it's very often misused, but it's meaning is essential to a clear explanation of this topic, so if you misuse it in the explanation you'll just end up with confusion. I think people giving explainers like this need to be careful to get their concepts right, especially core ones such as exposure. As to how to introduce the correct (rather than 'strict') use of exposure, why not just explain what it means? One of the reasons people don't know what it means is that people rarely give explanations. Old text books did.

  • @camilo8cheryl
    @camilo8cheryl 4 місяці тому

    WoW! Nose bleed👍

  • @SirTubeALotMore
    @SirTubeALotMore 4 місяці тому

    #Nikon, why do you confuse us so much 😢 We shouldn't be forced to watch YT channels to understand your products!

    • @chiftele08
      @chiftele08 4 місяці тому +1

      It's not nikon thing, all brands have sensors like this. Nikon has mostly ISO invariant sensors, the dual gain sensors are more in the Canon brand. That's the reason, you heard less about this topic than for example Canon users.

    • @b34k97
      @b34k97 4 місяці тому +1

      What? Electronics are complicated and to get the most out of it, you need to learn how it works at a fundamental level. Simplified user settings, generalized for all users, can only cover so many cases.