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I'm sorry, but while you may be a photography fan, you don't know what you're talking about here. Stacking is quite the opposite of a "ghetto" version of a lon

by dgacmu 8y ago

I'm sorry, but while you may be a photography fan, you don't know what you're talking about here. Stacking is quite the opposite of a "ghetto" version of a long exposure - it's the fundamental building block of being able to do the equivalent of a long exposure without its associated problems (motion blur from both camera and subject, high sensor noise if you turn up the gain, and over-saturating any bright spots). Stacking is the de facto technique used for DSLR astrophotography for exactly these reasons -- see https://photographingspace.com/stacking-vs-single/ https://photographingspace.com/stacking-vs-single/ However, you're ignoring the _very substantial_ challenges of merging many exposures taken on a handheld camera. Image stabilization is great, but there's a lot of motion over, say, 1 second on a hand-held camera. Much more than the typical IS algorithm is designed to handle. The techniques are non-trivial: http://graphics.stanford.edu/talks/seeinthedark-public-15sep16.key.pdf http://graphics.stanford.edu/talks/seeinthedark-public-15sep... There's a lot going on to accomplish this. It starts with the ability to do high-speed burst reads of raw data from the CCD (so that individual frames don't get motion blurred, and raw so you can process before you lose any fidelity by RGB conversion), and requires a lot of computational horsepower to perform alignment and do merging. I don't know what the Pixel's algorithms are, but merging of many images with hand-held camera motion benefits from state of the art results in applying CNNs to the problem, at least, from some of the results from Vladlen Koltun's group at Intel (who I'd put at the forefront of this, along with Marc Levoy's group at Google): http://vladlen.info/publications/learning-see-dark/ http://vladlen.info/publications/learning-see-dark/ I wouldn't be so quick to dismiss the technical meat behind state of the art low-light photography on cell phones.

endorphone 8y ago
"you don't know what you're talking about here" You literally repeated exactly what I said image stacking was, yet lead off by claiming that I don't know what I'm talking about. Classic. The goal of both is to achieve the exact same result -- more photons for a given pixel. Stacking is a necessary compromise under certain circumstances -- lack of sufficient stabilization, particularly noisy sensor or environment, etc. Further, this implementation is clearly long exposures (note the blur rather than strobe).
- dgacmu 8y ago
  Sorry, but no - stacking is as much about dynamic range adaptation as noise, and that's why I'm arguing against your terming it a "ghetto version of a long exposure". It's not. A long exposure has a fundamental problem with saturation, as well as noise. It's not just about lack of stabilization, there's also the motion of the subject. Computational approaches can compensate for subject motion - long exposures cannot. Computational approaches can do dynamic range adaptation to avoid blow-out due to CCD pixel saturation. Long exposures cannot. If you read the slides from the Levoy talk I cited, you'll note that they explicitly choose to under-expose the individual exposures to minimize motion blur and blowout. (Marc is now at Google continuing his work on computational photography, and his group contributes to many of the cool things you see on the Pixel series.)
  - endorphone 8y ago
    "Computational approaches can compensate for subject motion" But they don't. They don't in this example. Moving subjects are a blur. As an aside, of course stacked photo frames are underexposed because it wouldn't make much sense otherwise. Computational photography can do interesting things and holds a tremendous amount of promise. However every single example that I can find of this mode -- across the many astroturfed pages -- show a longer exposure than what the stock app normally allows. And with that the requisite blurring of any moving subject.
    - hug 8y ago
      Are you arguing that EIS over a series of burst photos is incapable of making things better? Everything I can see you saying -- much if it agreeable, like the fact that long-exposure OIS makes a lot of what this technology currently does possible without it -- is simply handwaving away the fact that EIS-over-burst with OIS can achieve things that OIS cannot by itself. It seems to me that it's patently true that EIS has some benefits, and those benefits can be realised over the top of OIS. There's obviously still a fair limit to OIS. I have somewhat shaky hands and even using something like Olympus' top range 5-axis IBIS, which is the best I've ever seen, I can still only shoot at 1/10". What can EIS do with a burst of 3x 1/20" exposures? Probably counter for my shaking a bit, at least. (If not for subject movement, yet.) I simply do not see why you're discounting this so heavily.

by dgacmu 8y ago

endorphone 8y ago

"you don't know what you're talking about here" You literally repeated exactly what I said image stacking was, yet lead off by claiming that I don't know what I'm talking about. Classic. The goal of both is to achieve the exact same result -- more photons for a given pixel. Stacking is a necessary compromise under certain circumstances -- lack of sufficient stabilization, particularly noisy sensor or environment, etc. Further, this implementation is clearly long exposures (note the blur rather than strobe).

dgacmu 8y ago
Sorry, but no - stacking is as much about dynamic range adaptation as noise, and that's why I'm arguing against your terming it a "ghetto version of a long exposure". It's not. A long exposure has a fundamental problem with saturation, as well as noise. It's not just about lack of stabilization, there's also the motion of the subject. Computational approaches can compensate for subject motion - long exposures cannot. Computational approaches can do dynamic range adaptation to avoid blow-out due to CCD pixel saturation. Long exposures cannot. If you read the slides from the Levoy talk I cited, you'll note that they explicitly choose to under-expose the individual exposures to minimize motion blur and blowout. (Marc is now at Google continuing his work on computational photography, and his group contributes to many of the cool things you see on the Pixel series.)
- endorphone 8y ago
  "Computational approaches can compensate for subject motion" But they don't. They don't in this example. Moving subjects are a blur. As an aside, of course stacked photo frames are underexposed because it wouldn't make much sense otherwise. Computational photography can do interesting things and holds a tremendous amount of promise. However every single example that I can find of this mode -- across the many astroturfed pages -- show a longer exposure than what the stock app normally allows. And with that the requisite blurring of any moving subject.
  - hug 8y ago
    Are you arguing that EIS over a series of burst photos is incapable of making things better? Everything I can see you saying -- much if it agreeable, like the fact that long-exposure OIS makes a lot of what this technology currently does possible without it -- is simply handwaving away the fact that EIS-over-burst with OIS can achieve things that OIS cannot by itself. It seems to me that it's patently true that EIS has some benefits, and those benefits can be realised over the top of OIS. There's obviously still a fair limit to OIS. I have somewhat shaky hands and even using something like Olympus' top range 5-axis IBIS, which is the best I've ever seen, I can still only shoot at 1/10". What can EIS do with a burst of 3x 1/20" exposures? Probably counter for my shaking a bit, at least. (If not for subject movement, yet.) I simply do not see why you're discounting this so heavily.