6 ms·

> Focus it on a dark spot, and the camera is inactive. It only knows how to calibrate itself against lightness to define the image. I don't know much about pho

by tomp 12y ago

> Focus it on a dark spot, and the camera is inactive. It only knows how to calibrate itself against lightness to define the image. I don't know much about photography, but AFAIK, modern cameras need contrast to calibrate themselves, not lightness (or darkness). Point the camera towards a dark corner, nothing. Point it towards the sun, nothing. Point it towards a sharp edge of a shadow, or any other high-contrast area, an voila, focus!

Hobotron1 12y ago
That doesn't support the narrative the author constructed before fact-finding, so it's left out.
- danilocampos 12y ago
  So to your mind it's more likely that the author is telling fish stories than it is the dominant financial caste ended up optimizing a given piece of tech to their best interest? Bokay.
  - briandear 12y ago
    And you're such an angry bitter person that you automatically assume everything is racist? What are the qualifications of the article's author? You must have an exhausting life seeing racism behind every tree. What about the guys at Fuji film? Is their film anti-white and Asian biased? This whole discussion is absurd. Next thing we'll hear is that swimming pools are racist.
    - dang 12y ago
      > And you're such an angry bitter person Please don't express disagreement this way on Hacker News, regardless of how strongly you disagree.
    - danilocampos 12y ago
      >This whole discussion is absurd. Next thing we'll hear is that swimming pools are racist. Um. For a long time they were. Public pools were subject to racial segregation. Glad we have an expert on racism like yourself to help set us all straight here!
    - anthonyb 12y ago
      You might not like the way he says it, but go back and read the article: Kathy Connor, an executive at Kodak, told Roth the company didn’t develop a better film for rendering different gradations of brown until economic pressure came from a very different source: Kodak’s professional accounts. Two of their biggest clients were chocolate confectioners, who were dissatisfied with the film’s ability to render the difference between chocolates of different darknesses. “Also,” Connor says, “furniture manufacturers were complaining that stains and wood grains in their advertisement photos were not true to life.” How is that not racist? The film wasn't an issue when it was just people of colour coming out poorly, but when it's chocolate and furniture being badly exposed, then they develop a new film.
  - tedunangst 12y ago
    It's called crying wolf. Some aspects of photography may be optimized for whites; that doesn't mean everything is designed to make life harder for blacks. My camera apparently has the opposite problem. I can't autofocus on anything that's solid white. Did I accidentally buy the "black" model?
  - coldtea 12y ago
    Or he just knows about optics and physics. Besides, where's the "racism" in the dominant financial caste optimizing a given piece of tech to their best interests? It's a commercial product, so you optimize it for your main market, which, for most of photography's life has been white.
    - anthonyb 12y ago
      Er, that is pretty much a textbook example of racism.
      - coldtea 12y ago
        Only if you have never opened a dictionary or an actual textbook. A textbook example of racism is: "These people are inferior/primitive/stupid/immoral because they are black" (from which the colloraries come, like: "Lets exploit these infrerior people for slave labor". Or "I don't want these inferior people in my restaurant.) This case is, on the other hand: "Black people in the US don't have us much income (a fact), and are much fewer than white people (another fact). We should better optimize our film for the most common buyer, which would be white people". This has nothing to do with racism, it's basic economics. In fact if blacks were the most affluent or populous group, the same companies would target THEM in a heartbeat.
  - vernie 12y ago
    It's spelled "bokeh"
DannoHung 12y ago
Right, but a shadow on dark skin is much lower contrast than a shadow on light skin. The most contrast you are going to find on a dark skinned face is on the eyes. But even then, you can run into problems if, for example, they are wearing sunglasses or you're not close enough to get the focus to lock on the distinction between their eyes. This might not be a problem in a brightly lit scene, as long as you are using manual white balance (or, well, shooting RAW so you can adjust all that shit after the fact), but as you go to darker locations, you can definitely have an issue. A possible solution to this would be using infrared depth sensing rather than contrast or phase detection or a laser rangefinding system for autofocusing.
vinkelhake 12y ago
You're talking about auto focus and it's true that focus detectors in modern cameras need some contrast to work. Cameras use lightness/color for auto exposure (and auto white-balance). If you shoot a picture of a white sheet of paper with auto exposure on, cameras will typically try to adjust exposure so that it comes out looking gray-ish.
fennecfoxen 12y ago
You're not just going for focus, though. You're going for a finished product with dynamic range -- it's easy to perfectly focus onto a dark black blob, but that doesn't make it recognizable as a human being. You might need to overexpose the rest of the frame, so that the skintone darks are bright enough to be interesting. That's doable, but it takes either a human touch or a digital camera with facial-recognition technology to figure out that's what's happening instead of just going for the bright zones. (And then you get a bright white blob if there's a white guy in the frame.)
- omonra 12y ago
  You can't auto-focus on a black bob. You need difference in lightness (also known as contrast) - pls see: https://www.youtube.com/watch?v=jsDJ8g2qx5k https://www.youtube.com/watch?v=jsDJ8g2qx5k

by tomp 12y ago

Hobotron1 12y ago

That doesn't support the narrative the author constructed before fact-finding, so it's left out.

danilocampos 12y ago
So to your mind it's more likely that the author is telling fish stories than it is the dominant financial caste ended up optimizing a given piece of tech to their best interest? Bokay.
- briandear 12y ago
  And you're such an angry bitter person that you automatically assume everything is racist? What are the qualifications of the article's author? You must have an exhausting life seeing racism behind every tree. What about the guys at Fuji film? Is their film anti-white and Asian biased? This whole discussion is absurd. Next thing we'll hear is that swimming pools are racist.
  - dang 12y ago
    > And you're such an angry bitter person Please don't express disagreement this way on Hacker News, regardless of how strongly you disagree.
  - danilocampos 12y ago
    >This whole discussion is absurd. Next thing we'll hear is that swimming pools are racist. Um. For a long time they were. Public pools were subject to racial segregation. Glad we have an expert on racism like yourself to help set us all straight here!
  - anthonyb 12y ago
    You might not like the way he says it, but go back and read the article: Kathy Connor, an executive at Kodak, told Roth the company didn’t develop a better film for rendering different gradations of brown until economic pressure came from a very different source: Kodak’s professional accounts. Two of their biggest clients were chocolate confectioners, who were dissatisfied with the film’s ability to render the difference between chocolates of different darknesses. “Also,” Connor says, “furniture manufacturers were complaining that stains and wood grains in their advertisement photos were not true to life.” How is that not racist? The film wasn't an issue when it was just people of colour coming out poorly, but when it's chocolate and furniture being badly exposed, then they develop a new film.
- tedunangst 12y ago
  It's called crying wolf. Some aspects of photography may be optimized for whites; that doesn't mean everything is designed to make life harder for blacks. My camera apparently has the opposite problem. I can't autofocus on anything that's solid white. Did I accidentally buy the "black" model?
- coldtea 12y ago
  Or he just knows about optics and physics. Besides, where's the "racism" in the dominant financial caste optimizing a given piece of tech to their best interests? It's a commercial product, so you optimize it for your main market, which, for most of photography's life has been white.
  - anthonyb 12y ago
    Er, that is pretty much a textbook example of racism.
    - coldtea 12y ago
      Only if you have never opened a dictionary or an actual textbook. A textbook example of racism is: "These people are inferior/primitive/stupid/immoral because they are black" (from which the colloraries come, like: "Lets exploit these infrerior people for slave labor". Or "I don't want these inferior people in my restaurant.) This case is, on the other hand: "Black people in the US don't have us much income (a fact), and are much fewer than white people (another fact). We should better optimize our film for the most common buyer, which would be white people". This has nothing to do with racism, it's basic economics. In fact if blacks were the most affluent or populous group, the same companies would target THEM in a heartbeat.
- vernie 12y ago
  It's spelled "bokeh"

DannoHung 12y ago

Right, but a shadow on dark skin is much lower contrast than a shadow on light skin. The most contrast you are going to find on a dark skinned face is on the eyes. But even then, you can run into problems if, for example, they are wearing sunglasses or you're not close enough to get the focus to lock on the distinction between their eyes. This might not be a problem in a brightly lit scene, as long as you are using manual white balance (or, well, shooting RAW so you can adjust all that shit after the fact), but as you go to darker locations, you can definitely have an issue. A possible solution to this would be using infrared depth sensing rather than contrast or phase detection or a laser rangefinding system for autofocusing.

vinkelhake 12y ago

You're talking about auto focus and it's true that focus detectors in modern cameras need some contrast to work. Cameras use lightness/color for auto exposure (and auto white-balance). If you shoot a picture of a white sheet of paper with auto exposure on, cameras will typically try to adjust exposure so that it comes out looking gray-ish.

fennecfoxen 12y ago

You're not just going for focus, though. You're going for a finished product with dynamic range -- it's easy to perfectly focus onto a dark black blob, but that doesn't make it recognizable as a human being. You might need to overexpose the rest of the frame, so that the skintone darks are bright enough to be interesting. That's doable, but it takes either a human touch or a digital camera with facial-recognition technology to figure out that's what's happening instead of just going for the bright zones. (And then you get a bright white blob if there's a white guy in the frame.)

omonra 12y ago
You can't auto-focus on a black bob. You need difference in lightness (also known as contrast) - pls see: https://www.youtube.com/watch?v=jsDJ8g2qx5k https://www.youtube.com/watch?v=jsDJ8g2qx5k