• Members 1387 posts
    March 25, 2026, 9:34 p.m.

    In most descriptions, I stop reading as soon as it says:- "ISO sets sensor sensitivity" (my emphasis) ...

    ... it does not do so and I've never seen proof that it does.

  • March 25, 2026, 9:43 p.m.

    It may in certain circumstances - so called dual native ISO sensors, where sensitivity is triggered by hardware. Otherwise we can say that "ISO sets camera sensitivity", where camera sensitivity denotes some relation of scene/object brightness and corresponing recorded image pixel values.
    Of course purists do not buy such layman definition :)

    BTW, I believe the exposure triangle ;)

  • Members 1775 posts
    March 25, 2026, 11:13 p.m.

    Although with digital cameras the Exposure Triangle doesn't apply as it used to for film, I still think it relevant in that it contains concepts that are useful, especially if only relying on ooc jpegs.

  • Members 1970 posts
    March 26, 2026, 12:17 a.m.

    It’s sort of easy,..

    We know that the more total light that reaches your sensor, the less the noise you’ll have in your image.
    The total light of an exposure is only effected by aperture and shutter speed

    General Exposure process:
    1) Start with Base ISO

    2) Now make your two creative decisions :
    -Choose and set the lowest F number (and the appropriate focal distance) that will give you your desired FOV
    -Choose and set the slowest shutter speed that will still give you your desired protection against movement blur (or set some other preferred “creative” shutter speed)

    3)
    - If the brightness of the image is now too low with these “creative settings”, you can raise the ISO to increase the brightness, making sure that any desired highlights do not clip too much.
    ...on the other hand,
    - If the brightness of the image is too high and highlights are clipped, then you need to find a way to reduce the amount of light coming in

    Please note that if your sensor has a dual gain (e.g. the Nikon Z7 has a second stage gain that kicks in at ISO 400) and if you want/need to raise the ISO, then it’s usually worth choosing at least 400 (in this case)

    This general exposure process will result in an image that meets your creative choices and has the lowest noise levels.

    It may sound like a slow process but, with a little practice, it can be done very quickly. Using the live histogram on digital camera, like the Z7, is a possibility to easily see these results as you make the adjustments.

    It is, IMO, largely a matter of personal choice if you want to call this an exposure “triangle” or not.
    Just remember:
    -Two things effect exposure
    -Three things effect the “exposure + resulting brightness” of the image

  • Members 1387 posts
    March 26, 2026, 1:17 a.m.

    Interesting how often Aptina-licensed dual-gain sensors are getting mentioned in this thread ...

  • Members 93 posts
    March 26, 2026, 2:03 a.m.

    And the more information.

    The histogram is only going to show you a representation of the current JPEG settings though, not what the RAW file is capable of saving.

  • Members 2639 posts
    March 26, 2026, 7:09 a.m.

    deleted and reposted.

  • Members 2639 posts
    March 26, 2026, 7:16 a.m.

    not just relying on jpegs, in the studio i stream live hdmi to large monitors so i need to display close to correct exposure/ image brightness to the client as im shooting. iso also plays a big part in recording the exposure settings on paper for different styles of lighting. eg: shutter speed, aperture, iso and strobe output and physical location.

  • Members 2639 posts
    March 26, 2026, 7:22 a.m.

    wait for 10 years and you will have variable gain sensors, we could have them now but companies are milking the system for as long as they can 😁

  • Members 2639 posts
    March 26, 2026, 7:38 a.m.
  • Members 1970 posts
    March 26, 2026, 11:16 a.m.

    yes, indeed. With more "signal" in that information, the better the Signal to Noise ratio.

    Yes, unfortunately true, but since we don't have live "RAW histograms", the live histogram is the best available tool.
    It's also fairly easy to learn how much "headroom" is available for RAW highlights in a particular camera and sort of make appropriate small adjustments while taking the shot

  • Members 1387 posts
    March 26, 2026, 2 p.m.

    Agreed ... assuming that "total light" is Hm which is the average lux-seconds at the sensor image plane.

    Yep!

    Two of my cameras are raw-only and send the camera ISO setting in metadata to the raw converter which brightens the converter's Review image accordingly.

  • Members 1387 posts
    March 26, 2026, 2:10 p.m.

    Another misleading statement courtesy of AI ...

    Nope ... yet again, the literature ignores basic optics to dumb down the Infamous Triangle for the punters.

  • Members 1387 posts
    March 26, 2026, 2:31 p.m.

    Amplifying output signals from a sensor does not change it's sensitivity - so no proof there, sorry.

  • March 26, 2026, 4:54 p.m.

    It seems that you brought up this subject so that it could act as a straw man and entice others to enter the arguments, which were fully rehearsed in several threads here ages ago.

    Please do a search on "exposure triangle" and you will see how much time has already been wasted on it.

    David

  • Members 2524 posts
    March 26, 2026, 6:31 p.m.

    Ok, the exposure triangle is nonsense to those who understand how a sensor performs technically. The arguments are well known.

    But it is useful to those just starting to approach photography as it helps the understand aperture and shutter speed. Sometimes when somebody is at the beginning of their photographic journey, some simplification is useful to get them over the first stage.

  • Members 1387 posts
    March 26, 2026, 6:57 p.m.

    Might as well send it to the Dumpster then.

  • March 26, 2026, 7:02 p.m.

    I may understand all the technicality, but for me (as a casual photographer) "triangular" relation of shooting parameters [which affect resulting image brightness] is not nonsense. Sure we could think of better terms (ISO is the most misunderstood one), but having film background, I use this relation almost intuitively. Even in Auto-ISO mode (my preferred setting) :)

    Anecdotal evidence too :)
    ISO value is more noticeable than aperture value in my camera EVF. If I see 12800 (maximum for Auto-ISO) in normal shooting conditions then I know must have accidentally turned aperture dial into very wrong position (F/16), happens sometimes in cold weather, using gloves.

  • Members 1970 posts
    March 26, 2026, 7:04 p.m.

    Well I got the chance here with this thread to show everyone my fantastic general exposure method ;-)