RAW file sizes

Discussion in 'Digital Photography' started by Conrad, Nov 12, 2005.

  1. Conrad

    Conrad Guest

    Hi,

    Interesting comparison of RAW file sizes from my 8 megapixel Canon
    350XT (10+ MB at full resolution) and my 6 megapixel Fuji S7000 (12+ MB
    at full resolution). The latter is not using Fuji's proprietary
    doubling to 12 megapixels.
    Apparently, the smaller sensor Fuji is yielding more information than
    the larger sensor size Canon.

    Best,

    Conrad
    Camp Sherman, Oregon
    Conrad, Nov 12, 2005
    #1
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  2. "Conrad" <> writes:

    > Hi,
    >
    > Interesting comparison of RAW file sizes from my 8 megapixel Canon
    > 350XT (10+ MB at full resolution) and my 6 megapixel Fuji S7000 (12+ MB
    > at full resolution). The latter is not using Fuji's proprietary
    > doubling to 12 megapixels.
    > Apparently, the smaller sensor Fuji is yielding more information than
    > the larger sensor size Canon.


    The Canon raw files are obviously compressed, presumably using a
    lossless algorithm.

    --
    Måns Rullgård
    =?iso-8859-1?q?M=E5ns_Rullg=E5rd?=, Nov 12, 2005
    #2
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  3. Conrad

    Martin Brown Guest

    Conrad wrote:

    > Hi,
    >
    > Interesting comparison of RAW file sizes from my 8 megapixel Canon
    > 350XT (10+ MB at full resolution) and my 6 megapixel Fuji S7000 (12+ MB
    > at full resolution). The latter is not using Fuji's proprietary
    > doubling to 12 megapixels.
    > Apparently, the smaller sensor Fuji is yielding more information than
    > the larger sensor size Canon.


    If you put a couple of sample files of the same scene up on the web
    somewhere it is possible to measure the information content.

    I would hazard a guess that Canon is doing lossless compression of a
    12bit per channel 8Mpixel stream to get 12MB with about 15% compression
    and Fuji is saving 6Mpixels at 16bits per channel uncompressed as 12MB.

    I would be very surprised if the Fuji really was making use of more than
    12 of the 16 bits it appears to be saving in its raw format.

    Never confuse file size with information content...

    Regards,
    Martin Brown
    Martin Brown, Nov 12, 2005
    #3
  4. Conrad

    Bill Hilton Guest

    > Conrad writes ...
    >
    >Interesting comparison of RAW file sizes from my 8 megapixel Canon
    >350XT (10+ MB at full resolution) and my 6 megapixel Fuji S7000 (12+ MB
    >at full resolution).
    >Apparently, the smaller sensor Fuji is yielding more information than
    >the larger sensor size Canon.


    I think you are reaching the wrong conclusion for two reasons ...
    first, Canon RAW files are compressed losslessly ... second, a noisy
    file will compress more than a clean file, which you can verify with
    your Canon by shooting the identical scene (use a tripod) at the lowest
    and highest ISO settings ... the higher ISO image will have a good bit
    larger file size but it doesn't have "more information", it just has
    more noise.

    > ... the smaller sensor Fuji is yielding more information ...


    Or a lot more noise, in an uncompressed format :)

    Bill
    Bill Hilton, Nov 12, 2005
    #4
  5. Conrad

    al-Farrob Guest

    Bill Hilton wrote:

    >> Conrad writes ...
    >>

    [snip]
    > file will compress more than a clean file, which you can verify with


    Didn't you mean: ... will compress less... ?

    [snip]
    >
    > Bill


    --
    al-Farrob
    http://www.al-farrob.com - new photos every week
    al-Farrob, Nov 12, 2005
    #5
  6. Conrad

    Jim Guest

    "Conrad" <> wrote in message
    news:...
    > Hi,
    >
    > Interesting comparison of RAW file sizes from my 8 megapixel Canon
    > 350XT (10+ MB at full resolution) and my 6 megapixel Fuji S7000 (12+ MB
    > at full resolution). The latter is not using Fuji's proprietary
    > doubling to 12 megapixels.
    > Apparently, the smaller sensor Fuji is yielding more information than
    > the larger sensor size Canon.

    No it can't. Canon is using a lossless compression scheme whereas Fuji
    isn't.
    The only true test of this is the amount of memory that an image requires.
    The file sizes by themselves give no clues as to the amount of memory that
    is required.
    Jim
    >
    > Best,
    >
    > Conrad
    > Camp Sherman, Oregon
    >
    Jim, Nov 12, 2005
    #6
  7. Martin Brown <|||newspam|||@nezumi.demon.co.uk> writes:

    > Conrad wrote:
    >
    >> Hi,
    >> Interesting comparison of RAW file sizes from my 8 megapixel Canon
    >> 350XT (10+ MB at full resolution) and my 6 megapixel Fuji S7000 (12+ MB
    >> at full resolution). The latter is not using Fuji's proprietary
    >> doubling to 12 megapixels.
    >> Apparently, the smaller sensor Fuji is yielding more information than
    >> the larger sensor size Canon.

    >
    > If you put a couple of sample files of the same scene up on the web
    > somewhere it is possible to measure the information content.
    >
    > I would hazard a guess that Canon is doing lossless compression of a
    > 12bit per channel 8Mpixel stream to get 12MB with about 15%


    This theory is supported by the fact that Canon raw files compress
    very little with zip-like compression programs. I tested a sample
    with bzip2, and got a 1.017:1 compression ratio, compared to 2.378:1
    for the same image uncompressed.

    > compression and Fuji is saving 6Mpixels at 16bits per channel
    > uncompressed as 12MB.


    I don't have a Fuji, so I can't test those files.

    > I would be very surprised if the Fuji really was making use of more
    > than 12 of the 16 bits it appears to be saving in its raw format.
    >
    > Never confuse file size with information content...


    The size after compression with a good program gives a reasonable
    indication of information content.

    --
    Måns Rullgård
    =?iso-8859-1?q?M=E5ns_Rullg=E5rd?=, Nov 12, 2005
    #7
  8. Conrad

    Bill Hilton Guest

    >> file will compress more than a clean file, which you can verify with

    > al-Farrob writes ...
    >
    >Didn't you mean: ... will compress less... ?


    Yes that's what I meant but not what I wrote :) Thanks for catching it
    ....

    Bill
    Bill Hilton, Nov 12, 2005
    #8
  9. Conrad

    al-Farrob Guest

    Bill Hilton wrote:

    >>> file will compress more than a clean file, which you can verify with

    >
    >> al-Farrob writes ...
    >>
    >>Didn't you mean: ... will compress less... ?

    >
    > Yes that's what I meant but not what I wrote :) Thanks for catching it
    > ...
    >
    > Bill


    To not increase confusion on the OP's mind :)

    --
    al-Farrob
    http://www.al-farrob.com - new photos every week
    al-Farrob, Nov 12, 2005
    #9
  10. Conrad

    kctan Guest

    Fuji sensors' chip is different from Canon known as Super CCD and the
    placement of photosensors are not in rows and columns but alternating. It
    has 2 photodiodes for 1 photo sensor and "cheats" 1 extra pixel. Claim to be
    better but not up to expectation.

    "Conrad" <> wrote in message
    news:...
    > Hi,
    >
    > Interesting comparison of RAW file sizes from my 8 megapixel Canon
    > 350XT (10+ MB at full resolution) and my 6 megapixel Fuji S7000 (12+ MB
    > at full resolution). The latter is not using Fuji's proprietary
    > doubling to 12 megapixels.
    > Apparently, the smaller sensor Fuji is yielding more information than
    > the larger sensor size Canon.
    >
    > Best,
    >
    > Conrad
    > Camp Sherman, Oregon
    >
    kctan, Nov 12, 2005
    #10
  11. "Conrad" <> writes:

    > Interesting comparison of RAW file sizes from my 8 megapixel Canon
    > 350XT (10+ MB at full resolution) and my 6 megapixel Fuji S7000 (12+ MB
    > at full resolution). The latter is not using Fuji's proprietary
    > doubling to 12 megapixels.
    > Apparently, the smaller sensor Fuji is yielding more information than
    > the larger sensor size Canon.


    Or storing it less efficiently.

    My 6MP Fuji S2 pro produces 12MB raw files also, but they compress to
    less than 5MB when converted to Adobe DNG, and that should be a
    lossless conversion from a Fuji RAW file.
    --
    David Dyer-Bennet, <mailto:>, <http://www.dd-b.net/dd-b/>
    RKBA: <http://noguns-nomoney.com/> <http://www.dd-b.net/carry/>
    Pics: <http://dd-b.lighthunters.net/> <http://www.dd-b.net/dd-b/SnapshotAlbum/>
    Dragaera/Steven Brust: <http://dragaera.info/>
    David Dyer-Bennet, Nov 12, 2005
    #11
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