• Members 509 posts
    April 12, 2023, 9 p.m.

    I have this thing about the way photographers tend to think about perspective. All over the web, in books and magazines going back decades you can see things along the lines of:

    "Tele lenses flatten the image by compressing perspective. Wide lenses increase depth by expanding perspective".

    These errors are another example of confusing correlation and causation and you see it everywhere. Perspective is managed by moving closer or further from your subject, not by changing focal length. Tele lenses do not compress anything, distance does. The reason wide angle lenses give big noses is because you stand too close to the nose in order to fill the frame. The reason why the error persists, I think, is because when you use a tele lens, you photograph things that are far away and when everything is far away it all looks about the same size. And the only time you notice this is when you use a tele. And when you use a wide, your subject is tiny, so you naturally move closer. In both cases it is quite natural to jump to conclusions about causation. And most of the time mis-understanding the cause doesn't harm getting the shot, so it's really a silly thing to get wound up by.

    I can't quite work out whether this is also true about the exposure triangle. Does using it make you shoot things incorrectly? Given I don't actually understand what the ISO knob does, it's difficult to be sure.

  • Members 2303 posts
    April 12, 2023, 9:05 p.m.

    www.aperturebuzz.com/extended-iso/

  • Foundation 1464 posts
    April 12, 2023, 9:09 p.m.

    You know, I was just thinking the same thing.

    I am also thinking that it sets a very poor example for the level of discourse we come here for.

    Say cheese!

    David

  • Members 125 posts
    April 12, 2023, 9:10 p.m.

    Why do you always imply that:

    1. The “exposure triangle” describes exposure?
    2. All elements of the exposure triangle have a direct impact on each other (related to exposure) instead of a weak correlation?

    This is false.

  • Foundation 1464 posts
    April 12, 2023, 9:13 p.m.

    I was wondering why that fact hadnt been pointed out before in this discussion.

    David

  • Members 2303 posts
    April 12, 2023, 9:13 p.m.

    My daughter just drops it off at a lab in the city where she lives and they email you a link to the digital files. some companies scanners are very poor but the one my daughter is using is very good and the files are 8 meg from a fuji film scanner. the files look fairly good btu there is very little room to PP them in photoshop. havent taken a full roll with the new trip 35 yet so have no idea how it is giong to preform. i did pull it apart and clean it up and it seems to work good from what i can tell. all good fun though. my 20 yold daughter is loveing film cameras atm and im loving finding them and fixing them up ready for use and shooting a roll or 2.

  • Members 142 posts
    April 12, 2023, 9:16 p.m.

    Read and learn what's in these two posts

    Original post of the thread:
    dprevived.com/t/the-exposure-triangle-is-misleading-and-unnecessary/1602/

    Additional comment:
    dprevived.com/t/the-exposure-triangle-is-misleading-and-unnecessary/1602/post/12851/

    If you learn what's in these two you'll be 99% of the way to where you need to be.

  • Members 2303 posts
    April 12, 2023, 9:17 p.m.

    im printing all the images on my canon pro10s as all the labs are only printing from the scans and there prints are very poor. its not cheap printing from my printer but at least i know the prints will last for a long time.

  • Members 125 posts
    April 12, 2023, 9:17 p.m.

    This statement carries so much baggage that a ship would sink under its weight. This is akin to saying:

    • Really, there is no fundamental reason for having an AWB setting in camera at all.
    • Really, there is no fundamental reason for having a NR setting in camera at all.

    I would agree if you would say: “Really, there is no fundamental reason for having an ISO control in my workflow at all.”

    But this over-generalization is just another red herring.

  • April 12, 2023, 9:23 p.m.

    But we agreed that 'exposure' means amount of light (per unit area) - it can't mean both.

    Only for reversal film, and then it also depends on how you process the film. BTW, apart from reversal films the 'speed point' is at the toe of the curve, so it says very little about how light or dark the negative looks in absolute terms. So the idea that 'exposure' has a had link to how light or dark the picture looks with film is wide of the mark, certainly for any negative process, and even with reversal. But you've given a good example of how the triangle confuses people, it leads them to conflate exposure and lightness, which is wrong.

    The core misunderstanding about sensor speed is thinking that a sensor has a 'speed' according to ISO, and that 'speed' and 'sensitivity' would mean the same thing when talking about sensors.

    What is a 'light signal'? If it's light, then a transistor can't boost it. If it's an electronic signal representing light then boosting it won't change the amount of light that it represents.

    That's the trap that lies in intuition which isn't based on knowledge of the subject. The key thing about light, with respect to noise, is how many photons there are, and however much you boost the signal representing a number of photons it doesn't change the number of photons that there were.

    I'm not sure what you mean by the question. Amplification can do all sorts of things, but one of the things it doesn't to appreciably is increase noise (or decrease the SNR). The SNT produced by a good digital camera at its lowest ISO with optimal exposure is in the low to mid 40 dBs. A decently designed amplifier might have an SNR of 90dB or more, so the noise generated by the amplifier will be 50 dB below the shot noise, that's insignificant. The reason for variable gain is mainly to match the ADC input level to the requirements of the ADC. Increasing the gain actually results in less noise, at the cost of a smaller maximum input.

    Only for colour slide, which was very much a minority film, and even then is ignoring the processing element. And if you look at colour slide ISO, it was based not only on standard processing but a standard projector bulb power and screen size. Strictly, if you had a different projector or projecting to a different size you should have changed the speed rating. You don't view a digital raw file directly, so what colour slides were like isn't apposite.

  • April 12, 2023, 9:25 p.m.

    Please do explain what this baggage is. Not in terms of what you think it's like, but what it is, if it's anything at all.

  • April 12, 2023, 9:28 p.m.

    So before you see them, and judge 'exposure' form how dark it is, the film (negative or reversal?) has been developed, scanned, digitally processed and rendered. All those stages affect how light or dark it looks.

  • Members 132 posts
    April 12, 2023, 9:29 p.m.

    I think the main sticking point for you is that you seem to have the impression that the ISO knob somehow turns up the light and hence, is a component of exposure. It does not. Typically, the ISO knob will turn up an electrical signal produced by the sensor after the exposure. The result will be a brighter end result, but the exposure has not been increased, and whatever noise was present in that initial exposure will become more visually apparent. Increasing the exposure itself (light+aperture+SS) will also produce a brighter end result, but with less apparent noise because, unlike raising the ISO, a greater exposure will result in an also greater signal to noise ratio. If ISO was an equal component of exposure, the result would be the same either way, but it is not.

  • Members 125 posts
    April 12, 2023, 9:35 p.m.

    This statement is false. All credible sources that describe the exposure triangle say that aperture & shutter speed are responsible for exposure.

    As the first statement is already wrong, the implication is that this one is also wrong.

    Gain is about ADC sampling, not about light generation. No idea where these statements come from. I’ve never read a credible source explaining it that way, which is by the way also wrong (not only the statement in itself, but also that it is described like that).

  • April 12, 2023, 9:39 p.m.

    I don't always do that. I didn't do that here. What I said was what were the misconceptions that arose from the triangle. Someone seeing something labelled 'exposure triangle', and seeing that it had three sides or components might reasonably (and usually does) conclude that those three components are what constitute 'exposure', especially if no-one represents that they don't. Worse, many of the sources that utilise the triangle say exactly that the three sides do together represent exposure.

    Someone seeing a diagram with three sides, and no differentiation between them, might reasonably (and usually does) conclude that the factors represented by the sides are equal in effect (on exposure), and since two of them are certainly independent, might reasonably (and usually does) conclude that the third is also, especially if no-one represents that they aren't. Worse, many of the sources that utilise the triangle say exactly that the three sides are equal in effect (on exposure) and are independent.

    What is false is your representation of what I 'always say'

  • April 12, 2023, 9:46 p.m.

    No true Scotsman describes the exposure triangle.

    There's only one illicit negative around here, and it wasn't mine.

    There's that Scotsman again.

  • April 12, 2023, 9:55 p.m.

    Why is the fact that in ye olde dayes of digital we were told fairy stories relevant?

  • Members 2303 posts
    April 12, 2023, 9:59 p.m.

    only relying on the cameras metering atm as she was sick of shooting the full manual 35mm cameras
    where to set the correct exposure you needed to set.
    1: shutter speed
    2: f stop
    3: film speed asa
    4: exposure comp depending on backlighting .which is directly part of asa setting.
    5: if indoors set the flash to all numbers 1,2,3 🙄and distance.

    to her it was a pain in the a.... so i gave my old

    i-img1200x802-16657336118wc22u4128.jpg

    and she loves it. because it is fully automatic including flash. its a quality point and shoot 35mm camera. very sort after buy the young ones. so im interested in her experience with the trip 35 as its not as sophisticated as the konica.

    i-img1200x802-16657336118wc22u4128.jpg

    JPG, 46.1 KB, uploaded by DonaldB on April 12, 2023.