18 ms·

How does lossless compression in Fuji RAF files work? (2020)

110 points by dsego 1y ago

vjvjvjvjghv 1y ago
There are always these crazy discussions in photo forums where people are arguing that uncompressed RAW files are better than lossless compressed.
- jsheard 1y ago
  Glad to hear that audiophiles have some competition in who can invent the most pointless things to split hairs over. The photo guys need to start taping magic rocks to their cameras to really keep up though.
  - badlibrarian 1y ago
    They weren't just rocks. They were brilliant pebbles. https://web.archive.org/web/20150220012844/http://www.machinadynamica.com/machina31.htm https://web.archive.org/web/20150220012844/http://www.machin...
  - miladyincontrol 1y ago
    The worst part is its often in areas people improperly understand the benefits and downsides. Biggest problem with good raw compression is you have a linear DNG, half processed essentially. Great, the file size is smaller, but now you miss data that processes like AI denoise can benefit from as the image is already debayered. On the flip side, good compression like DNG 1.7 spec's jpeg-xl compression is borderline magic. Lossless is actually lossless. The lossy flavour is so good even at 105 megapixels in 16 bit (per color channel) I would challenge anyone to spot a noticeable difference compared to the original, a file possibly 20x it's size. On a tangent, bits per channel is yet another part people split hairs over. 14 vs 16 has almost no difference, no the colours are not 'better' even in a full 16 bit workflow, the only real world perceivable difference is your darkest darks are more precise and under extreme editing conditions do look a little better if being raised extensibly in post. I digress 16 is bigger than 14 and yay marketing. Looping back to compression, 14 bit raws without compression are padded to 16 bit lengths due to word sizes and file constraints. This bit throws off the less technically minded who make all sorts of assumptions about file sizes and being 'more lightweight to edit'.
    - adgjlsfhk1 1y ago
      I'm kind of surprised we haven't seen things like 16 bit luminence, 12 bit chromanance. (I guess to do that before debayering would require RGBW pixels or something like that)
  - mlyle 1y ago
    The problem is camera marketing makes it really unclear what you're actually getting. Really lossless? Does it trigger more on-body processing? Does it throw away bits to be "visually lossless"? If you shoot a few thousand photos and then find you can't fix exposure as well as you'd hoped and the whole batch is worse, it's a pretty big disappointment, so it's smart to be risk adverse and skeptical.
    - jcynix 1y ago
      >The problem is camera marketing [...] IMHO marketing is almost always (part of) the problem. They shouldn't drink or smoke that stuff … Equating "lossless" with "visually lossless" or some other phrase is newspeak. We could call a JPEG of quality >= 95 (or 96 .. 99) visually lossless too then. Losslessness is easy to define: compress something, then uncompress it again and both the original and the uncompressed file should compute to the same (cryptographic) checksum.
  - beAbU 1y ago
    There's probably an untapped market for sd cards with "special" holographic stickers on them retailing for $100 each.
    - jsheard 1y ago
      Maybe an audiophile SD card would also produce better photos in a camera? You never know until you try! https://www.whathifi.com/news/sony-claims-high-end-sd-card-offers-premium-sound https://www.whathifi.com/news/sony-claims-high-end-sd-card-o...
- matja 1y ago
  Those discussions I feel are fuelled by manufacturers like Sony saying [0] things like: Lossless compressed RAW: ... This is a popular format that occupies less space with minimal quality loss. "minimal" "loss"? That's not "no loss", so what exactly is it? [0] https://www.sony.co.uk/electronics/support/articles/00257081 https://www.sony.co.uk/electronics/support/articles/00257081
  - gappa 1y ago
    I actually asked Sony Support about that. Their reply: "We can confirm that with Lossless compressed RAW there is a minimal quality loss. To have no impact on image quality I suggest using Uncompressed RAW files." Lossless isn't what it used to be.
    - benoliver999 1y ago
      They read it lessloss I guess
    - vjvjvjvjghv 1y ago
      That's insane. I honestly thought that lossless basically means to run zip over the file and not more. Gotta hate companies these days with their dishonesty. "Lossless" means "lossy". "Unlimited" means "limited to 50GB".
    - smugglerFlynn 1y ago
      Seems you just got 1st line robo-reply repeating what public resources state. Does not say much about actual compression algorithm Sony uses.
      - gappa 1y ago
        Their first reply was "we have passed your question to a higher technical team", then they came back four days later with the above reply. I was enquiring about the A7R mark V, which introduced the much needed "lossless" option. I think I asked because I wondered why they kept the uncompressed option and because experts warned that Sony did that before with "lossless" formats.
- manoDev 1y ago
  It’s because manufacturers keep inventing their own formats instead of using plain DNG, and you can only figure out the difference reverse engineering the file. Even for the same manufacturer and file type, they may change encoding details between models or firmware revisions. There are situations where they may decrease the bit depth of the final image if there’s not enough dynamic range, there are situations where even though the file is “uncompressed” the camera already does noise reduction and essentially compresses detail in the image, and so on…
  - danhau 1y ago
    Manufacturers not supporting DNG is so annoying. But of course they do it. Allows them to sell licenses to software vendors like Adobe or Capture One.
  - brnt 1y ago
    How is DNG tooling these days? It's been ages since I checked, but it used have near zero support in (FLOSS) tools (including ffmpeg/imagemagick). You even had to use Adobe's Windows converter.
    - scblock 1y ago
      DNG is well supported by the typical raw libraries in my experience. My Ricoh records DNG natively, and I work with the results in rawtherapee and darktable. I am less sure about ffmpeg or imagemagick as I don't really automate raw processing.
      - brnt 1y ago
        I see however that DNG support is still read-only-ish, e.g. libraw still can't convert to DNG [1]. Most camera's still output raw in their own formats, which may not and probably should not be what you store them as, long term. [1] https://github.com/ImageMagick/ImageMagick/issues/6344 https://github.com/ImageMagick/ImageMagick/issues/6344
  - tecleandor 1y ago
    DNG license might include some legal stuff that probably they don't want in their devices. https://helpx.adobe.com/camera-raw/digital-negative.html#dng https://helpx.adobe.com/camera-raw/digital-negative.html#dng
- agloe_dreams 1y ago
  Honestly the best argument for uncompressed is actually nothing to do with file quality or loss - it's that Apple only supports uncompressed Fuji RAWs. You cannot preview or process lossless compressed Fuji RAWs on iOS natively but the uncompressed files are equal to Apple's own RAWs in support. On the field, it is sadly worth every byte to be able to grab a file directly off the camera and tweak it or send it to an editor. :/
  - vjvjvjvjghv 1y ago
    The problem is that the size difference between compressed and uncompressed is enormous. This adds up quickly if you shoot sports or wildlife with 20fps bursts.
  - CharlesW 1y ago
    > Honestly the best argument for uncompressed is actually nothing to do with file quality or loss - it's that Apple only supports uncompressed Fuji RAWs. Nitro¹ (macOS, xOS), the spiritual successor to Aperture², does support Fuji compressed RAW: https://www.gentlemencoders.com/extended-raw/ https://www.gentlemencoders.com/extended-raw/ (I left Lightroom for Nitro + Apple Photos a couple years ago, and can strongly recommend Nitro to fellow photo takers.) ¹ https://www.gentlemencoders.com/nitro-for-macos/ https://www.gentlemencoders.com/nitro-for-macos/ ² https://www.gentlemencoders.com/about/ https://www.gentlemencoders.com/about/
- jcynix 1y ago
  These forum discussions seem unconnected to reality IMO. Sometimes funny, more often strange, like audiophile discussions about oxygen free copper cables. Why? The Fuji X-T4 and X-S20 here produce images of 6240x4160 pixels, but I almost never look at images in 1:1. My 4K monitors, mostly set to 2K, display 2560 x 1440 pixels. And even when switch them to their full 4K resolution I don't view my images in 1:1 obviously. And the tablet l'm typing this comment on offers "meager" 1800 × 2880 pixels. Most family members look at images on their "smart" devices nowadays, where 2K or 4K aren't present. So even decompressed images are fine for them. I have my cameras configured to take both JPEG (fine) + RAW (lossless) of course. Fuji JPEGs (and Canon ... etc too) are fine for most casual viewers. And if I want to crop certain parts, or adjust certain details (esp exposure), I have my RAW images as a fallback. Storage? My SD cards are 256GB and my disks are definitely not a problem either.
  - LeifCarrotson 1y ago
    I almost never look at full images in 1:1, either, but I find very often that I have the wrong lens for an application and/or the wrong exposure. You don't have to go very far before you've cropped a 20 MP source image into a 4K or 2K image, and if that part of the image that you've wanted to highlight is not well-lit, well, exposure is logarithmic and I want all of that RAW color depth that the camera can find if I'm going to turn black or white into perceptually accurate colors. It's true that when my framing and exposure are great out of the box, I probably wouldn't notice or care if JPEG compression cut my file size by a factor of 4...but that's not always the case.
  - cogman10 1y ago
    The main reason my wife shoots lossless is touch-up editing in light room. You can rescue some pretty crappy photos when all the sensor data is present.
  - FireBeyond 1y ago
    > My 4K monitors, mostly set to 2K, display 2560 x 1440 pixels. And even when switch them to their full 4K resolution I don't view my images in 1:1 obviously. macOS, but my understanding of Retina is that even if your effective resolution is lower (e.g., my 6K ProDisplay has a resolution of 3008x1692), applications can designate regions to be "original resolution," so I'm getting the image's original resolution in the editing window or region.
the_lucifer 1y ago
As someone who shoots on Fujifilm (XT-3), this was an intensely fascinating read. Thanks, now I have half a mind to sit down and re-implement this code, just to get a feel of how it works.
- vadansky 1y ago
  I've been thinking of buying that camera for a while, do you recommend it? Do you have anything to say that will finally push me over the edge to actually but it?
  - jagaerglad 1y ago
    I have the same one and I can definitely recommend it. It depends what your camera experience is, but if you have had one that collected dust on a shelf in the past, I can guarantee you that this one is more fun to use and has a much lower risk of dust collection
  - Analemma_ 1y ago
    I recently upgraded from an XT-3 to an XT-5, but loved my XT-3 and would still recommend it as a good purchase if you can find a decent deal on one in good condition. Fuji’s AF is not the best in the business, so I wouldn’t recommend one if you’re planning on using it for e.g. sports photography, but apart from that the XT series has no real downsides. The physical dials for ISO+exposure+shutter speed are fantastic and Fuji’s color processing makes images that I just enjoy looking at, even if they’re not as strictly neutral and accurate as what you’d get from someone else.
    - ninjin 1y ago
      Fujifilm's whole X-mount series is wonderful and while I shoot "full-frame" M mount to remain interoperable between digital and film, there is no doubt in my mind that I would have a Fujifilm X-mount series if I only shot digital based on how much fun they have been when I have borrowed/tested them. Great "enthusiast level" cameras, great glass, solid build, everything has a button/dial, does not break the bank, and I actually know more than one professional photographer that shoots them and one of them even shooting sports!
yboulkaid 1y ago
I wonder if something about this explains why Fuji RAF files are the only RAW files that make Lightroom struggle. I never heard the fans on my M1 mac until I started processing those RAF files, they're not even that large but something about them makes Lightroom struggle. And judging by posts on photography forums, I'm not the only one either
- ImPleadThe5th 1y ago
  I moved away from Adobe recently and ended up trying out Affinity Photo. Opening a RAF file would regularly seize my entire computer. I always wondered if it was a deadlock situation, because it doesn't spit out any overflow errors.
- kjkjadksj 1y ago
  Lightroom still is terrible for fuji raws from a worm standpoint. Almost looks like they use bilinear debayering. Dcraw is night and day better.
- jcynix 1y ago
  Lightroom struggles with Fuji's unconventional sensor pattern. Other programs like Darktable, GraphicConverter, Luminar Neo or FastRawViewer don't make fans of my M1 audible.
- _7acn 1y ago
  I'm not sure what causes the terrible RAF handling in Lightroom, but it's a fairly well-known issue. Lightroom produces so-called "worming" and apparently this is related to the X-Trans sensor which requires a different decoding algorithm. On my end, I can recommend Capture One - the handling here is perfect, though you do have to get used to the UI unfortunately

110 points by dsego 1y ago

There are always these crazy discussions in photo forums where people are arguing that uncompressed RAW files are better than lossless compressed.

jsheard 1y ago
Glad to hear that audiophiles have some competition in who can invent the most pointless things to split hairs over. The photo guys need to start taping magic rocks to their cameras to really keep up though.
- badlibrarian 1y ago
  They weren't just rocks. They were brilliant pebbles. https://web.archive.org/web/20150220012844/http://www.machinadynamica.com/machina31.htm https://web.archive.org/web/20150220012844/http://www.machin...
- miladyincontrol 1y ago
  The worst part is its often in areas people improperly understand the benefits and downsides. Biggest problem with good raw compression is you have a linear DNG, half processed essentially. Great, the file size is smaller, but now you miss data that processes like AI denoise can benefit from as the image is already debayered. On the flip side, good compression like DNG 1.7 spec's jpeg-xl compression is borderline magic. Lossless is actually lossless. The lossy flavour is so good even at 105 megapixels in 16 bit (per color channel) I would challenge anyone to spot a noticeable difference compared to the original, a file possibly 20x it's size. On a tangent, bits per channel is yet another part people split hairs over. 14 vs 16 has almost no difference, no the colours are not 'better' even in a full 16 bit workflow, the only real world perceivable difference is your darkest darks are more precise and under extreme editing conditions do look a little better if being raised extensibly in post. I digress 16 is bigger than 14 and yay marketing. Looping back to compression, 14 bit raws without compression are padded to 16 bit lengths due to word sizes and file constraints. This bit throws off the less technically minded who make all sorts of assumptions about file sizes and being 'more lightweight to edit'.
  - adgjlsfhk1 1y ago
    I'm kind of surprised we haven't seen things like 16 bit luminence, 12 bit chromanance. (I guess to do that before debayering would require RGBW pixels or something like that)
- mlyle 1y ago
  The problem is camera marketing makes it really unclear what you're actually getting. Really lossless? Does it trigger more on-body processing? Does it throw away bits to be "visually lossless"? If you shoot a few thousand photos and then find you can't fix exposure as well as you'd hoped and the whole batch is worse, it's a pretty big disappointment, so it's smart to be risk adverse and skeptical.
  - jcynix 1y ago
    >The problem is camera marketing [...] IMHO marketing is almost always (part of) the problem. They shouldn't drink or smoke that stuff … Equating "lossless" with "visually lossless" or some other phrase is newspeak. We could call a JPEG of quality >= 95 (or 96 .. 99) visually lossless too then. Losslessness is easy to define: compress something, then uncompress it again and both the original and the uncompressed file should compute to the same (cryptographic) checksum.
- beAbU 1y ago
  There's probably an untapped market for sd cards with "special" holographic stickers on them retailing for $100 each.
  - jsheard 1y ago
    Maybe an audiophile SD card would also produce better photos in a camera? You never know until you try! https://www.whathifi.com/news/sony-claims-high-end-sd-card-offers-premium-sound https://www.whathifi.com/news/sony-claims-high-end-sd-card-o...
matja 1y ago
Those discussions I feel are fuelled by manufacturers like Sony saying [0] things like: Lossless compressed RAW: ... This is a popular format that occupies less space with minimal quality loss. "minimal" "loss"? That's not "no loss", so what exactly is it? [0] https://www.sony.co.uk/electronics/support/articles/00257081 https://www.sony.co.uk/electronics/support/articles/00257081
- gappa 1y ago
  I actually asked Sony Support about that. Their reply: "We can confirm that with Lossless compressed RAW there is a minimal quality loss. To have no impact on image quality I suggest using Uncompressed RAW files." Lossless isn't what it used to be.
  - benoliver999 1y ago
    They read it lessloss I guess
  - vjvjvjvjghv 1y ago
    That's insane. I honestly thought that lossless basically means to run zip over the file and not more. Gotta hate companies these days with their dishonesty. "Lossless" means "lossy". "Unlimited" means "limited to 50GB".
  - smugglerFlynn 1y ago
    Seems you just got 1st line robo-reply repeating what public resources state. Does not say much about actual compression algorithm Sony uses.
    - gappa 1y ago
      Their first reply was "we have passed your question to a higher technical team", then they came back four days later with the above reply. I was enquiring about the A7R mark V, which introduced the much needed "lossless" option. I think I asked because I wondered why they kept the uncompressed option and because experts warned that Sony did that before with "lossless" formats.
manoDev 1y ago
It’s because manufacturers keep inventing their own formats instead of using plain DNG, and you can only figure out the difference reverse engineering the file. Even for the same manufacturer and file type, they may change encoding details between models or firmware revisions. There are situations where they may decrease the bit depth of the final image if there’s not enough dynamic range, there are situations where even though the file is “uncompressed” the camera already does noise reduction and essentially compresses detail in the image, and so on…
- danhau 1y ago
  Manufacturers not supporting DNG is so annoying. But of course they do it. Allows them to sell licenses to software vendors like Adobe or Capture One.
- brnt 1y ago
  How is DNG tooling these days? It's been ages since I checked, but it used have near zero support in (FLOSS) tools (including ffmpeg/imagemagick). You even had to use Adobe's Windows converter.
  - scblock 1y ago
    DNG is well supported by the typical raw libraries in my experience. My Ricoh records DNG natively, and I work with the results in rawtherapee and darktable. I am less sure about ffmpeg or imagemagick as I don't really automate raw processing.
    - brnt 1y ago
      I see however that DNG support is still read-only-ish, e.g. libraw still can't convert to DNG [1]. Most camera's still output raw in their own formats, which may not and probably should not be what you store them as, long term. [1] https://github.com/ImageMagick/ImageMagick/issues/6344 https://github.com/ImageMagick/ImageMagick/issues/6344
- tecleandor 1y ago
  DNG license might include some legal stuff that probably they don't want in their devices. https://helpx.adobe.com/camera-raw/digital-negative.html#dng https://helpx.adobe.com/camera-raw/digital-negative.html#dng
agloe_dreams 1y ago
Honestly the best argument for uncompressed is actually nothing to do with file quality or loss - it's that Apple only supports uncompressed Fuji RAWs. You cannot preview or process lossless compressed Fuji RAWs on iOS natively but the uncompressed files are equal to Apple's own RAWs in support. On the field, it is sadly worth every byte to be able to grab a file directly off the camera and tweak it or send it to an editor. :/
- vjvjvjvjghv 1y ago
  The problem is that the size difference between compressed and uncompressed is enormous. This adds up quickly if you shoot sports or wildlife with 20fps bursts.
- CharlesW 1y ago
  > Honestly the best argument for uncompressed is actually nothing to do with file quality or loss - it's that Apple only supports uncompressed Fuji RAWs. Nitro¹ (macOS, xOS), the spiritual successor to Aperture², does support Fuji compressed RAW: https://www.gentlemencoders.com/extended-raw/ https://www.gentlemencoders.com/extended-raw/ (I left Lightroom for Nitro + Apple Photos a couple years ago, and can strongly recommend Nitro to fellow photo takers.) ¹ https://www.gentlemencoders.com/nitro-for-macos/ https://www.gentlemencoders.com/nitro-for-macos/ ² https://www.gentlemencoders.com/about/ https://www.gentlemencoders.com/about/
jcynix 1y ago
These forum discussions seem unconnected to reality IMO. Sometimes funny, more often strange, like audiophile discussions about oxygen free copper cables. Why? The Fuji X-T4 and X-S20 here produce images of 6240x4160 pixels, but I almost never look at images in 1:1. My 4K monitors, mostly set to 2K, display 2560 x 1440 pixels. And even when switch them to their full 4K resolution I don't view my images in 1:1 obviously. And the tablet l'm typing this comment on offers "meager" 1800 × 2880 pixels. Most family members look at images on their "smart" devices nowadays, where 2K or 4K aren't present. So even decompressed images are fine for them. I have my cameras configured to take both JPEG (fine) + RAW (lossless) of course. Fuji JPEGs (and Canon ... etc too) are fine for most casual viewers. And if I want to crop certain parts, or adjust certain details (esp exposure), I have my RAW images as a fallback. Storage? My SD cards are 256GB and my disks are definitely not a problem either.
- LeifCarrotson 1y ago
  I almost never look at full images in 1:1, either, but I find very often that I have the wrong lens for an application and/or the wrong exposure. You don't have to go very far before you've cropped a 20 MP source image into a 4K or 2K image, and if that part of the image that you've wanted to highlight is not well-lit, well, exposure is logarithmic and I want all of that RAW color depth that the camera can find if I'm going to turn black or white into perceptually accurate colors. It's true that when my framing and exposure are great out of the box, I probably wouldn't notice or care if JPEG compression cut my file size by a factor of 4...but that's not always the case.
- cogman10 1y ago
  The main reason my wife shoots lossless is touch-up editing in light room. You can rescue some pretty crappy photos when all the sensor data is present.
- FireBeyond 1y ago
  > My 4K monitors, mostly set to 2K, display 2560 x 1440 pixels. And even when switch them to their full 4K resolution I don't view my images in 1:1 obviously. macOS, but my understanding of Retina is that even if your effective resolution is lower (e.g., my 6K ProDisplay has a resolution of 3008x1692), applications can designate regions to be "original resolution," so I'm getting the image's original resolution in the editing window or region.

the_lucifer 1y ago

As someone who shoots on Fujifilm (XT-3), this was an intensely fascinating read. Thanks, now I have half a mind to sit down and re-implement this code, just to get a feel of how it works.

vadansky 1y ago
I've been thinking of buying that camera for a while, do you recommend it? Do you have anything to say that will finally push me over the edge to actually but it?
- jagaerglad 1y ago
  I have the same one and I can definitely recommend it. It depends what your camera experience is, but if you have had one that collected dust on a shelf in the past, I can guarantee you that this one is more fun to use and has a much lower risk of dust collection
- Analemma_ 1y ago
  I recently upgraded from an XT-3 to an XT-5, but loved my XT-3 and would still recommend it as a good purchase if you can find a decent deal on one in good condition. Fuji’s AF is not the best in the business, so I wouldn’t recommend one if you’re planning on using it for e.g. sports photography, but apart from that the XT series has no real downsides. The physical dials for ISO+exposure+shutter speed are fantastic and Fuji’s color processing makes images that I just enjoy looking at, even if they’re not as strictly neutral and accurate as what you’d get from someone else.
  - ninjin 1y ago
    Fujifilm's whole X-mount series is wonderful and while I shoot "full-frame" M mount to remain interoperable between digital and film, there is no doubt in my mind that I would have a Fujifilm X-mount series if I only shot digital based on how much fun they have been when I have borrowed/tested them. Great "enthusiast level" cameras, great glass, solid build, everything has a button/dial, does not break the bank, and I actually know more than one professional photographer that shoots them and one of them even shooting sports!

yboulkaid 1y ago

I wonder if something about this explains why Fuji RAF files are the only RAW files that make Lightroom struggle. I never heard the fans on my M1 mac until I started processing those RAF files, they're not even that large but something about them makes Lightroom struggle. And judging by posts on photography forums, I'm not the only one either

ImPleadThe5th 1y ago
I moved away from Adobe recently and ended up trying out Affinity Photo. Opening a RAF file would regularly seize my entire computer. I always wondered if it was a deadlock situation, because it doesn't spit out any overflow errors.
kjkjadksj 1y ago
Lightroom still is terrible for fuji raws from a worm standpoint. Almost looks like they use bilinear debayering. Dcraw is night and day better.
jcynix 1y ago
Lightroom struggles with Fuji's unconventional sensor pattern. Other programs like Darktable, GraphicConverter, Luminar Neo or FastRawViewer don't make fans of my M1 audible.
_7acn 1y ago
I'm not sure what causes the terrible RAF handling in Lightroom, but it's a fairly well-known issue. Lightroom produces so-called "worming" and apparently this is related to the X-Trans sensor which requires a different decoding algorithm. On my end, I can recommend Capture One - the handling here is perfect, though you do have to get used to the UI unfortunately