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"HDR images can be challenging to edit, because some decisions are effectively baked into the final JPG. To maximize latitude for editing, it’s possible to save

"HDR images can be challenging to edit, because some decisions are effectively baked into the final JPG. To maximize latitude for editing, it’s possible to save RAW images for each shot (an option in the app). However, this process takes the photographer out of the moment and requires expertise with RAW editing tools as well as additional storage." I wish at least 12bit (ideally 14 or 16bit) compressed image formats (like HEIF) took over jpeg on cameras. It's great to have raw as an option, but can we please just get rid of 8bit jpg as the default

ISL 6y ago
Part of the underlying challenge is that displays are, at best, 10-bit. Our imaging systems easily handle 14-bit depth, but the display systems cannot.
- dharma1 6y ago
  Yep. But you can do a lot more post-processing to bring all that latitude back to 8/10bit color space, than if you start with a 8bit jpeg. Same as when shooting high bit depth raw files
  - ISL 6y ago
    To me, the biggest limitation is the limited range in luminance. By design, half of my work (ig:@charliehagedorn) is in black and white. The difference in light intensity between sunlit snow and shadowed rock is often far, far more than 8 stops. While it is the job of the photographer, these days, to collapse the dynamic range enough to get it onto a screen, there is a huge depth of experience awaiting us the day that our displays reach parity with our sensors.
    - bscphil 6y ago
      > To me, the biggest limitation is the limited range in luminance. The difference in light intensity between sunlit snow and shadowed rock is often far, far more than 8 stops. The bit depth of a photo or display device is not the same as the dynamic range at which that photo is displayed. With traditional SDR image formats, on some screens a "0" pixel will be displayed at about 1 nit brightness, and a "255" pixel will be displayed at about 100 nits. But on other screens, the same pixel will be shown at 500 nits or more. Thus with SDR images, the luminance range depends on the characteristics of the display device in use, and not the fact that it's only an "8 bit" photo. "8 bit" ≠ "8 stops". On the other hand, on displays with very high peak brightness, you may get banding even with images that are properly dithered to take advantage of the full capabilities of the 8 bit range. The point of 10 bit and higher is that you can accurately capture all the details in between a very dark portion of an image and a very bright one without banding. The point of the new HDR standards (which are just now being introduced to images) is that luma is now on an absolute scale, so that you are no longer dependent on the characteristics of the individual display. (You have to have both together for either to be very useful.) But whether you're working with SDR or HDR, 8 bit or 10 bit, fundamentally the question of how many stops you can get (the display's true contrast) is a question of what the display is capable of reproducing, not the underlying technology you're working with.
      - ISL 6y ago
        I'd contend that a display that spans a dynamic range of a factor of 100 is only a 6.7-bit display. It is impossible to calibrate such a display to span 8 bits of intensity. It isn't the maximal intensity that matters, (to the extent that the viewer's eye can adapt to the differences in intensity between displays), but rather the number of subdivisions available between peak intensity and darkness. Totally agreed that improved bit-depth improves gradations/banding. An N+1-bit display has N bits between half-intensity and full intensity, twice as many bits as an N-bit display has. Another way to see that this matters is that imaging sensors are generally linear in their response to impinging light. The optimal way to display the output from a 14-bit sensor is a 14-bit (or higher) display.
        bscphil 6y ago
        > I'd contend that a display that spans a dynamic range of a factor of 100 is only a 6.7-bit display. It is impossible to calibrate such a display to span 8 bits of intensity. That's not what a nit is. A nit is a measurement of absolute brightness. You can have 256 gradations (8 bits) on a 100 nit display. You can have 1024 gradations (10 bits). You could have 65536. What's being measured here are two different things. Imagine I have a flashlight with adjustable brightness: if I turn it all the way up, that's what we're measuring when we talk about the nits of a display with with all white pixels. The bit depth is how many gradations the flashlight can display between full brightness and no light at all. So in fact a 100 nit display can have any bit depth. A stop is not a nit is not bit depth. (This is a simplification that is only completely accurate for SDR screens with sRGB gamut. With HDR and tagged images, part of the range created by the extra bit depth is for "impossible" values, stuff that is too bright or colorful for the screen to display, and has to be tonemapped by the display into the possible range.)
        ISL 6y ago
        First off -- thank you for this conversation. It has caused me to think more-deeply about the meaning of pixel-values in a display context. It has sent me into the standards, too. In particular, I found this document useful: http://www.color.org/WP40-Black_Point_Compensation_2010-07-27.pdf http://www.color.org/WP40-Black_Point_Compensation_2010-07-2... We agree that bit-depth is independent of maximum light output. Where we appear to disagree is on the meaning of an ideal bit, in particular whether or not it is acceptable for the (gamma-corrected) intensity difference between pixel-value 0 and pixel-value 1 to be greater than the base intensity of the display at pixel-value 0. I believe that I'm arguing for the concept depicted in Figure 3 of the document above (relative colorimetric), while you are arguing for the concept in Figure 4 (black-point compensation). There is an important pragmatism to your approach -- high contrast ratios are technically difficult, while higher-resolution gradations sitting atop a pedestal of minimum intensity may be more technically-feasible. Increased subdivisions between minimum intensity and maximum intensity do reduce banding, as you suggest. Such a rendering choice can portray the content of an image at the expense of the creator's intended contrast. A linear display output with no offset will yield an intensity proportional to the intensity value assigned to that pixel. Higher bit-depth does not make for greater intensity, but rather more gradations between maximum intensity and zero. As a scientist or as an artist, when specifying pixel values I expect the intensity, on a calibrated display, to reproduce a calibrated fraction of the maximum light intensity. It is helpful to understand that not all systems render with this intent. In the original reply, the thought-experiment display had a minimum brightness of 1 nit and a maximum brightness of 100 nits and 255 brightness levels between them. That spans a factor of 2^6.7. The discrepancy between our opinions represents differences in a choice of rendering intent. If I had to specify the rendering strategy for portraying 8-bit pixel values on such a display, it would have less contrast in the shadows than the highlights but equal contrast in the highlights when compared with an 8-bit display with a minimum brightness of 0.4 nits and a maximum brightness of 100 nits (which is capable of 2^8 dynamic range). Your strategy would yield uniform contrast spanning the shadows and highlights, but less contrast on the 1-100 nit display than the 0.4-100 nit display. In that situation, I suspect that most people would prefer your black-point compensated rendering strategy, as the shadows would not be crushed. I simply wouldn't market/sell it as a true 8-bit display, though I understand why a manufacturer would choose to do so. Thank you -- I learned something useful.
dstaley 6y ago
The iPhone defaults to HEIF, and all Android devices running at least Android 9 have the option to save images in HEIF. That being said, I have no idea if you get any of the benefits of a higher bit-depth.
- dharma1 6y ago
  I don't think the iPhone HEIF is 14/16bit. And I'm not sure a single shot on a sensor that small has that much dynamic range anyway, so you'd still want HDR+ style multiple exposures. Just wish the end result wasn't stored 8bit so you have more freedom to change the exposure/shadows/highlights after the shot is saved
  - dstaley 6y ago
    Yeah I think the big issue here is that HEIF is typically used to get JPEG level quality at a lower file size. Increased bit depth would negate those file savings, and I bet Apple/Google would just prefer you use RAW.
    - dharma1 6y ago
      14bit HEIF is still smaller than 8bit jpg. And lossless raw is easily 5-10x the size
- bscphil 6y ago
  > all Android devices running at least Android 9 have the option to save images in HEIF Can you tell me how I'd enable this on an Android 9 device? I've looked everywhere, even in the developer options, but I can't find it.
  - dstaley 6y ago
    Should be in your camera app. Where, exactly, depends on what device you have.
    - 6y ago
berkut 6y ago
Newer Canon mirrorless cameras now support HEIF (R5 and R6), and I think newer Sony ones will as well, so the groundswell might be starting in the higher-end. But iPhones have defaulted to using HEIF for years now I think, and no browser (even Safari) supports the format yet, so...
auxym 6y ago
Or AVIF

ISL 6y ago

Part of the underlying challenge is that displays are, at best, 10-bit. Our imaging systems easily handle 14-bit depth, but the display systems cannot.

dharma1 6y ago
Yep. But you can do a lot more post-processing to bring all that latitude back to 8/10bit color space, than if you start with a 8bit jpeg. Same as when shooting high bit depth raw files
- ISL 6y ago
  To me, the biggest limitation is the limited range in luminance. By design, half of my work (ig:@charliehagedorn) is in black and white. The difference in light intensity between sunlit snow and shadowed rock is often far, far more than 8 stops. While it is the job of the photographer, these days, to collapse the dynamic range enough to get it onto a screen, there is a huge depth of experience awaiting us the day that our displays reach parity with our sensors.
  - bscphil 6y ago
    > To me, the biggest limitation is the limited range in luminance. The difference in light intensity between sunlit snow and shadowed rock is often far, far more than 8 stops. The bit depth of a photo or display device is not the same as the dynamic range at which that photo is displayed. With traditional SDR image formats, on some screens a "0" pixel will be displayed at about 1 nit brightness, and a "255" pixel will be displayed at about 100 nits. But on other screens, the same pixel will be shown at 500 nits or more. Thus with SDR images, the luminance range depends on the characteristics of the display device in use, and not the fact that it's only an "8 bit" photo. "8 bit" ≠ "8 stops". On the other hand, on displays with very high peak brightness, you may get banding even with images that are properly dithered to take advantage of the full capabilities of the 8 bit range. The point of 10 bit and higher is that you can accurately capture all the details in between a very dark portion of an image and a very bright one without banding. The point of the new HDR standards (which are just now being introduced to images) is that luma is now on an absolute scale, so that you are no longer dependent on the characteristics of the individual display. (You have to have both together for either to be very useful.) But whether you're working with SDR or HDR, 8 bit or 10 bit, fundamentally the question of how many stops you can get (the display's true contrast) is a question of what the display is capable of reproducing, not the underlying technology you're working with.
    - ISL 6y ago
      I'd contend that a display that spans a dynamic range of a factor of 100 is only a 6.7-bit display. It is impossible to calibrate such a display to span 8 bits of intensity. It isn't the maximal intensity that matters, (to the extent that the viewer's eye can adapt to the differences in intensity between displays), but rather the number of subdivisions available between peak intensity and darkness. Totally agreed that improved bit-depth improves gradations/banding. An N+1-bit display has N bits between half-intensity and full intensity, twice as many bits as an N-bit display has. Another way to see that this matters is that imaging sensors are generally linear in their response to impinging light. The optimal way to display the output from a 14-bit sensor is a 14-bit (or higher) display.
      - bscphil 6y ago
        > I'd contend that a display that spans a dynamic range of a factor of 100 is only a 6.7-bit display. It is impossible to calibrate such a display to span 8 bits of intensity. That's not what a nit is. A nit is a measurement of absolute brightness. You can have 256 gradations (8 bits) on a 100 nit display. You can have 1024 gradations (10 bits). You could have 65536. What's being measured here are two different things. Imagine I have a flashlight with adjustable brightness: if I turn it all the way up, that's what we're measuring when we talk about the nits of a display with with all white pixels. The bit depth is how many gradations the flashlight can display between full brightness and no light at all. So in fact a 100 nit display can have any bit depth. A stop is not a nit is not bit depth. (This is a simplification that is only completely accurate for SDR screens with sRGB gamut. With HDR and tagged images, part of the range created by the extra bit depth is for "impossible" values, stuff that is too bright or colorful for the screen to display, and has to be tonemapped by the display into the possible range.)
        ISL 6y ago
        First off -- thank you for this conversation. It has caused me to think more-deeply about the meaning of pixel-values in a display context. It has sent me into the standards, too. In particular, I found this document useful: http://www.color.org/WP40-Black_Point_Compensation_2010-07-27.pdf http://www.color.org/WP40-Black_Point_Compensation_2010-07-2... We agree that bit-depth is independent of maximum light output. Where we appear to disagree is on the meaning of an ideal bit, in particular whether or not it is acceptable for the (gamma-corrected) intensity difference between pixel-value 0 and pixel-value 1 to be greater than the base intensity of the display at pixel-value 0. I believe that I'm arguing for the concept depicted in Figure 3 of the document above (relative colorimetric), while you are arguing for the concept in Figure 4 (black-point compensation). There is an important pragmatism to your approach -- high contrast ratios are technically difficult, while higher-resolution gradations sitting atop a pedestal of minimum intensity may be more technically-feasible. Increased subdivisions between minimum intensity and maximum intensity do reduce banding, as you suggest. Such a rendering choice can portray the content of an image at the expense of the creator's intended contrast. A linear display output with no offset will yield an intensity proportional to the intensity value assigned to that pixel. Higher bit-depth does not make for greater intensity, but rather more gradations between maximum intensity and zero. As a scientist or as an artist, when specifying pixel values I expect the intensity, on a calibrated display, to reproduce a calibrated fraction of the maximum light intensity. It is helpful to understand that not all systems render with this intent. In the original reply, the thought-experiment display had a minimum brightness of 1 nit and a maximum brightness of 100 nits and 255 brightness levels between them. That spans a factor of 2^6.7. The discrepancy between our opinions represents differences in a choice of rendering intent. If I had to specify the rendering strategy for portraying 8-bit pixel values on such a display, it would have less contrast in the shadows than the highlights but equal contrast in the highlights when compared with an 8-bit display with a minimum brightness of 0.4 nits and a maximum brightness of 100 nits (which is capable of 2^8 dynamic range). Your strategy would yield uniform contrast spanning the shadows and highlights, but less contrast on the 1-100 nit display than the 0.4-100 nit display. In that situation, I suspect that most people would prefer your black-point compensated rendering strategy, as the shadows would not be crushed. I simply wouldn't market/sell it as a true 8-bit display, though I understand why a manufacturer would choose to do so. Thank you -- I learned something useful.

dstaley 6y ago

The iPhone defaults to HEIF, and all Android devices running at least Android 9 have the option to save images in HEIF. That being said, I have no idea if you get any of the benefits of a higher bit-depth.

dharma1 6y ago
I don't think the iPhone HEIF is 14/16bit. And I'm not sure a single shot on a sensor that small has that much dynamic range anyway, so you'd still want HDR+ style multiple exposures. Just wish the end result wasn't stored 8bit so you have more freedom to change the exposure/shadows/highlights after the shot is saved
- dstaley 6y ago
  Yeah I think the big issue here is that HEIF is typically used to get JPEG level quality at a lower file size. Increased bit depth would negate those file savings, and I bet Apple/Google would just prefer you use RAW.
  - dharma1 6y ago
    14bit HEIF is still smaller than 8bit jpg. And lossless raw is easily 5-10x the size
bscphil 6y ago
> all Android devices running at least Android 9 have the option to save images in HEIF Can you tell me how I'd enable this on an Android 9 device? I've looked everywhere, even in the developer options, but I can't find it.
- dstaley 6y ago
  Should be in your camera app. Where, exactly, depends on what device you have.
  - 6y ago

berkut 6y ago

Newer Canon mirrorless cameras now support HEIF (R5 and R6), and I think newer Sony ones will as well, so the groundswell might be starting in the higher-end. But iPhones have defaulted to using HEIF for years now I think, and no browser (even Safari) supports the format yet, so...

auxym 6y ago

Or AVIF