6 ms·

Sure, photographs will still control aperture and exposure time — this just removes a constraint at one end: if you want shallow depth of field and motion blur,

by kps 11y ago

Sure, photographs will still control aperture and exposure time — this just removes a constraint at one end: if you want shallow depth of field and motion blur, you could use this method (and get extra bits) rather than an ND filter.

StavrosK 11y ago
Exactly. This is huge, and I was wondering why people didn't do it already. Or, for example, why don't cameras currently take multiple snapshots of the sensor? For example, if I'm exposing for 2 seconds, read the sensor at 0.1 sec (for the very bright lights) and again at 2 seconds, for the darker parts. That way, I can make an HDR image without having to take another photo. Is reading the sensor destructive to the data, somehow?
- EvanAnderson 11y ago
  Readout of a CCD is destructive. There are types of sensors that have non-destructive readout (Charge Injection Devices being one example: https://www.cis.rit.edu/research/CID/a_cid_is.htm https://www.cis.rit.edu/research/CID/a_cid_is.htm).
  - StavrosK 11y ago
    Very interesting, thank you.
  - kps 11y ago
    A sensor with per-pixel reset to zero on readout would seem to be ideal — then you could get cumulative counts without wasting valuable photon landing space on the die.
  - kuschku 11y ago
    Okay, but can’t I take 8 raw images and merge them into one image with 8 times higher dynamic range?
    - KingMob 11y ago
      Yes, but if I understand correctly, unless those images occur at the same time (or really, really close) you run into issues involving subject and camera motion.
    - altcognito 11y ago
      Yes, that's what modern cameras with the built in feature do. (although I'm not sure about 8 times) The article talks about this feature.
      - kuschku 11y ago
        Yes, but why can’t the camera do it continuously? Film at 240fps and provide a 60fps output with 10bit color depth.
        pto0239hn 11y ago
        Because the images would look funny. Imagine you're capturing someone running - at frame 1, they would be at position x, and at frame 2, they'll be at position x + 1. If you try to stack them together, you'll get a weird ghosting effect.
        kuschku 11y ago
        Well, that ghosting effect is also called motion blur. If I integrate continuously, that is.
        pto0239hn 11y ago
        Motion blur, but different parts of the image would be exposed differently due to the nature of HDR, resulting in an odd look. Imagine instead of a runner, that you're panning from a dark to light scene.
        kuschku 11y ago
jpablo 11y ago
That's just really a completely misguided statement. No mater how much you fumble with aperture and shutter speed there's simply no way to expand the camera sensor dynamic range without taking multiple exposures. Besides I have never seen "ordinary people" fumble with aperture size and exposure length so that's a solved problem. Sometimes it gives "wrong" results, like exposing for the highlights rather than the shadows, that's what this technology solves.
- kps 11y ago
  > there's simply no way to expand the camera sensor dynamic range without taking multiple exposures That's the point of this paper†. They expand dynamic range by having the detectors wrap around (discarding high bits) and then recover the high bits computationally. † here http://web.media.mit.edu/~hangzhao/modulo.html http://web.media.mit.edu/~hangzhao/modulo.html (linked by putterson in another comment)
  - jpablo 11y ago
    I know, I just don't see how it solves this issue. You couldn't solve the issue before "fumbling with aperture size and exposure length" The only thing I would consider that solves "fumble with aperture size and exposure length" would be huge ISO range (both ways) without any noise. > No more will photographers or even ordinary people have to fumble with aperture size and exposure length.
    - wanderingstan 11y ago
      > No mater how much you fumble with aperture and shutter speed there's simply no way to expand the camera sensor dynamic range without taking multiple exposures. > I just don't see how it solves this issue. http://rationalwiki.org/wiki/Argument_from_incredulity http://rationalwiki.org/wiki/Argument_from_incredulity
- dr_zoidberg 11y ago
  Some DSLRs and MILCs (and I think some semi-pro compacts too) have a wide enough dynamic range that they can work and HDR image from a single RAW file. Catch is, you have to shoot RAW and then process it with specific software. When it's done in-camera, it always is through multiple exposures. Even without specific software, you can work the effect from a single RAW file to get "multiple exposures" from it and then combine them into an HDR image.

by kps 11y ago

StavrosK 11y ago

Exactly. This is huge, and I was wondering why people didn't do it already. Or, for example, why don't cameras currently take multiple snapshots of the sensor? For example, if I'm exposing for 2 seconds, read the sensor at 0.1 sec (for the very bright lights) and again at 2 seconds, for the darker parts. That way, I can make an HDR image without having to take another photo. Is reading the sensor destructive to the data, somehow?

EvanAnderson 11y ago
Readout of a CCD is destructive. There are types of sensors that have non-destructive readout (Charge Injection Devices being one example: https://www.cis.rit.edu/research/CID/a_cid_is.htm https://www.cis.rit.edu/research/CID/a_cid_is.htm).
- StavrosK 11y ago
  Very interesting, thank you.
- kps 11y ago
  A sensor with per-pixel reset to zero on readout would seem to be ideal — then you could get cumulative counts without wasting valuable photon landing space on the die.
- kuschku 11y ago
  Okay, but can’t I take 8 raw images and merge them into one image with 8 times higher dynamic range?
  - KingMob 11y ago
    Yes, but if I understand correctly, unless those images occur at the same time (or really, really close) you run into issues involving subject and camera motion.
  - altcognito 11y ago
    Yes, that's what modern cameras with the built in feature do. (although I'm not sure about 8 times) The article talks about this feature.
    - kuschku 11y ago
      Yes, but why can’t the camera do it continuously? Film at 240fps and provide a 60fps output with 10bit color depth.
      - pto0239hn 11y ago
        Because the images would look funny. Imagine you're capturing someone running - at frame 1, they would be at position x, and at frame 2, they'll be at position x + 1. If you try to stack them together, you'll get a weird ghosting effect.
        kuschku 11y ago
        Well, that ghosting effect is also called motion blur. If I integrate continuously, that is.
        pto0239hn 11y ago
        Motion blur, but different parts of the image would be exposed differently due to the nature of HDR, resulting in an odd look. Imagine instead of a runner, that you're panning from a dark to light scene.
        kuschku 11y ago

jpablo 11y ago

That's just really a completely misguided statement. No mater how much you fumble with aperture and shutter speed there's simply no way to expand the camera sensor dynamic range without taking multiple exposures. Besides I have never seen "ordinary people" fumble with aperture size and exposure length so that's a solved problem. Sometimes it gives "wrong" results, like exposing for the highlights rather than the shadows, that's what this technology solves.

kps 11y ago
> there's simply no way to expand the camera sensor dynamic range without taking multiple exposures That's the point of this paper†. They expand dynamic range by having the detectors wrap around (discarding high bits) and then recover the high bits computationally. † here http://web.media.mit.edu/~hangzhao/modulo.html http://web.media.mit.edu/~hangzhao/modulo.html (linked by putterson in another comment)
- jpablo 11y ago
  I know, I just don't see how it solves this issue. You couldn't solve the issue before "fumbling with aperture size and exposure length" The only thing I would consider that solves "fumble with aperture size and exposure length" would be huge ISO range (both ways) without any noise. > No more will photographers or even ordinary people have to fumble with aperture size and exposure length.
  - wanderingstan 11y ago
    > No mater how much you fumble with aperture and shutter speed there's simply no way to expand the camera sensor dynamic range without taking multiple exposures. > I just don't see how it solves this issue. http://rationalwiki.org/wiki/Argument_from_incredulity http://rationalwiki.org/wiki/Argument_from_incredulity
dr_zoidberg 11y ago
Some DSLRs and MILCs (and I think some semi-pro compacts too) have a wide enough dynamic range that they can work and HDR image from a single RAW file. Catch is, you have to shoot RAW and then process it with specific software. When it's done in-camera, it always is through multiple exposures. Even without specific software, you can work the effect from a single RAW file to get "multiple exposures" from it and then combine them into an HDR image.