5 ms·

Capturing bigger differences between highlights and shadows (i.e. dynamic range) is one of the primary goals of camera manufacturers. It's one of the most criti

by creato 5y ago

Capturing bigger differences between highlights and shadows (i.e. dynamic range) is one of the primary goals of camera manufacturers. It's one of the most critical aspects of camera performance, and they're competing to deliver better dynamic range. We're stuck with it because it's a hard problem.

silisili 5y ago
So, not being argumentative but curious, and also rather uneducated here...why? Where is the big disconnect in that our own eyes can do these things so easily, and no camera can? It's not any insult to cameras, but a genuine question.
- adgjlsfhk1 5y ago
  The short answer is that human eyes have really good dynamic range (around 24 bits). For comparison, most monitors only have 8 bit pixels, and the best cameras have around 16 bits. That means that human eyes are much better at perceiving combinations of bright and dim areas at the same time.
  - silisili 5y ago
    Me being dumb, again. Why cannot our cameras have 24 bit or more range?
    - dagmx 5y ago
      Physics and data processing. Our eyes aren't actually 24 bit per frame. In fact our eyes are pretty shit. What they're good at is fairly quickly moving and adjusting, and are backed by a processor (our brain) that is capable of converting that data into a spatially aware image. In fact our brain doesn't even really see much of the view. It's filling in a lot of blanks based on the understanding of the scene. Cameras are trying to capture that into a still. You can capture multiple stills together with different exposures, but you're going to battle things like motion etc.. Most cameras these days are in the 10-14 bit range which is a function of the range the photosites will respond too before saturating, but also given that most displays are 8 bit, after a point there's just diminishing gains. 14 bits allows for a lot of latitude when shooting and processing.
    - kibibyte 5y ago
      I'm not an expert on this topic, but I'm certain it has to do with space constraints. Supporting more range of color depth means that the raw output of the sensor is necessarily bigger. This means we have some range of tradeoffs to make in the camera: * Save the sensor output directly as a RAW image onto storage. This means your storage medium can store fewer photos. You're also now beholden to the speed of your storage. Specialty photography like wildlife and sports impose requirements like being able to take lots of pictures per second; cameras solve this by having large memory buffers. Slow storage means the buffer fills up quicker. * Compress your RAW images with lossless algorithms. These do a decent job, but they still result in big files on storage media. Same problems as earlier point. Need quite a bit of memory and CPU on the camera to deal with this, and plus this now competes with how many shots per second you can buffer. * Compress your images with lossy algorithms (output RAW or JPEGs). Pretty much unacceptable since you don't get to decide what detail the algorithm removes. Of course, this also imposes hardware demands on the photographer's computer. Big images require: * Lots of storage. Maybe time to pay for a lot of cloud storage? * Fast storage too because otherwise Lightroom takes forever to load an image * Lots of RAM so that Lightroom can cache more images at once so you can flip back and forth with more ease. * Fast RAM and CPU so that Lightroom can do adjustments without much lag (some of this can be offloaded to GPU, but it's not a drastic improvement). Now, I think these problems are solvable today. They just require obscene amounts of money. I do want to add, RAW images by today's consumer-level cameras do support a fairly wide dynamic range. A skilled photographer will know how to work with RAW files to bring out details from the extreme ends of the range (e.g. dark skin against a bright background). But it does require setting up the shot well, and one can only capture so much range (e.g. I have a few bird pictures where part of the bird is still totally blown out and unrecoverable because of sunlight).
    - adgjlsfhk1 5y ago
      Also, I've done some more search and the 24 bit figure for the human eye is somewhat disputed. It looks like the actual figure is around 16 stops at a time, but our iris gives another 8 or so stops (but only after an adjustment period). Part of the answer for why dynamic range on modern cameras isn't better is that we're only starting to see consumer grade displays with more than 8 bits. Given that, most camera makers would rather put increased image quality resources towards upping the frame-rate or pixel density, which make it harder to get high dynamic range.
- chongli 5y ago
  Our eyes are not taking a single still photo, they’re taking in real life in real time. Our eyes constantly adapt to changing conditions as we look around a room. This capability is finite though, as anyone who has walked out of a dark room into the midday sun has experienced. The limitation in all photographic technologies has to do with the fundamental light gathering mechanism. In the case of photographic film, it is grains of photosensitive chemicals such as silver halides. In the case of digital cameras it is photosensitive semiconductors called CCDs or CMOS sensors. These sensors (chemical and digital) operate by collecting photons during the exposure. In either case, and with our eyes too, they can only collect so many photons before they “fill up.” In the case of film, this meant enough photons had arrived at the grain of silver halide to provide it with the energy needed to cause the reaction to take place. This reaction causes an irreversible change in the colour of the grain. In the case of digital sensors, when enough photons arrive the device stores its maximum possible charge which is then read out and converted to a number (usually the maximum number for that integer type). So then why can’t we make photographic technology that can gather a larger number of photons before “filling up”? It’s a tradeoff. The larger we make the (sensors or film grains) the more capacity for light gathering (called dynamic range) they have, but the lower the resolution they have. Unfortunately, in the world of consumer devices, resolution (megapixels) is king. The fundamental problem we’re dealing with in nature is that the dynamic range of real life is many orders of magnitude. Outdoor midday sunlight can be something like a hundred million photons per second per pixel whereas night time under starlight that falls to less than one photon per second per pixel.

by creato 5y ago

silisili 5y ago

So, not being argumentative but curious, and also rather uneducated here...why? Where is the big disconnect in that our own eyes can do these things so easily, and no camera can? It's not any insult to cameras, but a genuine question.

adgjlsfhk1 5y ago
The short answer is that human eyes have really good dynamic range (around 24 bits). For comparison, most monitors only have 8 bit pixels, and the best cameras have around 16 bits. That means that human eyes are much better at perceiving combinations of bright and dim areas at the same time.
- silisili 5y ago
  Me being dumb, again. Why cannot our cameras have 24 bit or more range?
  - dagmx 5y ago
    Physics and data processing. Our eyes aren't actually 24 bit per frame. In fact our eyes are pretty shit. What they're good at is fairly quickly moving and adjusting, and are backed by a processor (our brain) that is capable of converting that data into a spatially aware image. In fact our brain doesn't even really see much of the view. It's filling in a lot of blanks based on the understanding of the scene. Cameras are trying to capture that into a still. You can capture multiple stills together with different exposures, but you're going to battle things like motion etc.. Most cameras these days are in the 10-14 bit range which is a function of the range the photosites will respond too before saturating, but also given that most displays are 8 bit, after a point there's just diminishing gains. 14 bits allows for a lot of latitude when shooting and processing.
  - kibibyte 5y ago
    I'm not an expert on this topic, but I'm certain it has to do with space constraints. Supporting more range of color depth means that the raw output of the sensor is necessarily bigger. This means we have some range of tradeoffs to make in the camera: * Save the sensor output directly as a RAW image onto storage. This means your storage medium can store fewer photos. You're also now beholden to the speed of your storage. Specialty photography like wildlife and sports impose requirements like being able to take lots of pictures per second; cameras solve this by having large memory buffers. Slow storage means the buffer fills up quicker. * Compress your RAW images with lossless algorithms. These do a decent job, but they still result in big files on storage media. Same problems as earlier point. Need quite a bit of memory and CPU on the camera to deal with this, and plus this now competes with how many shots per second you can buffer. * Compress your images with lossy algorithms (output RAW or JPEGs). Pretty much unacceptable since you don't get to decide what detail the algorithm removes. Of course, this also imposes hardware demands on the photographer's computer. Big images require: * Lots of storage. Maybe time to pay for a lot of cloud storage? * Fast storage too because otherwise Lightroom takes forever to load an image * Lots of RAM so that Lightroom can cache more images at once so you can flip back and forth with more ease. * Fast RAM and CPU so that Lightroom can do adjustments without much lag (some of this can be offloaded to GPU, but it's not a drastic improvement). Now, I think these problems are solvable today. They just require obscene amounts of money. I do want to add, RAW images by today's consumer-level cameras do support a fairly wide dynamic range. A skilled photographer will know how to work with RAW files to bring out details from the extreme ends of the range (e.g. dark skin against a bright background). But it does require setting up the shot well, and one can only capture so much range (e.g. I have a few bird pictures where part of the bird is still totally blown out and unrecoverable because of sunlight).
  - adgjlsfhk1 5y ago
    Also, I've done some more search and the 24 bit figure for the human eye is somewhat disputed. It looks like the actual figure is around 16 stops at a time, but our iris gives another 8 or so stops (but only after an adjustment period). Part of the answer for why dynamic range on modern cameras isn't better is that we're only starting to see consumer grade displays with more than 8 bits. Given that, most camera makers would rather put increased image quality resources towards upping the frame-rate or pixel density, which make it harder to get high dynamic range.
chongli 5y ago
Our eyes are not taking a single still photo, they’re taking in real life in real time. Our eyes constantly adapt to changing conditions as we look around a room. This capability is finite though, as anyone who has walked out of a dark room into the midday sun has experienced. The limitation in all photographic technologies has to do with the fundamental light gathering mechanism. In the case of photographic film, it is grains of photosensitive chemicals such as silver halides. In the case of digital cameras it is photosensitive semiconductors called CCDs or CMOS sensors. These sensors (chemical and digital) operate by collecting photons during the exposure. In either case, and with our eyes too, they can only collect so many photons before they “fill up.” In the case of film, this meant enough photons had arrived at the grain of silver halide to provide it with the energy needed to cause the reaction to take place. This reaction causes an irreversible change in the colour of the grain. In the case of digital sensors, when enough photons arrive the device stores its maximum possible charge which is then read out and converted to a number (usually the maximum number for that integer type). So then why can’t we make photographic technology that can gather a larger number of photons before “filling up”? It’s a tradeoff. The larger we make the (sensors or film grains) the more capacity for light gathering (called dynamic range) they have, but the lower the resolution they have. Unfortunately, in the world of consumer devices, resolution (megapixels) is king. The fundamental problem we’re dealing with in nature is that the dynamic range of real life is many orders of magnitude. Outdoor midday sunlight can be something like a hundred million photons per second per pixel whereas night time under starlight that falls to less than one photon per second per pixel.