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Tim Daly's JPEGs: Sorting the fact from fiction

Discussion in 'AP Magazine Feedback & Suggestions' started by P_Stoddart, Apr 4, 2017.

  1. P_Stoddart

    P_Stoddart Well-Known Member

    Although I found the article interesting. and there is some useful nuggets of information.

    Generally make no sense to capture say a once in lifetime shot in 8 bit data format.

    Surely you are risking narrowing the dynamic range?

    He admits:

    "Compared to raw files, JPEGs record a scene in 8-bit per colour channel rather than the larger 12- or 14-bit used by raw. JPEGs therefore can be unforgiving of minor shooting errors such as exposure and white-balance mistakes."

    So you got to get exposure nearer the mark with JPEG.

    I found it's best to under expose then you can always lift in processing by using RAW shooting.

    JPEG is good for final print file say upload to online printing site.

    I shoot RAW+JPEG, yes it uses more space but I can see stuff with booting software. Then work on the RAW version.

    As for action shooting, every good photographer knows you don't depend on the FPS it about timing, you can get the shot with one click if you study and get the feel of your camera. Used to get really good action shots using a film camera which was hand wound full manual. :)

    Finally I am not sure the compression level in the cameras goes as low as software in photo editing.

    Therefore the images is being degraded which you will see on closer inspection.

    Now if you start printing big for exhibition you will see such artifacts if the compression is not at the very bottom level. Example you might go 30x20"

    I don't know camera makers quote their compression levels for their fine settings but I bet it is not the bottom compression level that the JPEG system can be set to.

    Best thing to do is shoot a test subject on your camera at say fine. Then take the raw and convert to JPEG at minimum compression see if you can see artifacts out of the camera's JPEG against the RAW to JPEG. I have done this and can see such loss in images.
     
  2. Roger_Provins

    Roger_Provins Well-Known Member

    Also the file sizes would give a good idea of the amount of compression used.
     
  3. Andrew Flannigan

    Andrew Flannigan Well-Known Member

    Some cameras store the compression ratio in the "compressed bits per pixel" tag where "1" stands for a ratio of 1:1 and "4" for 1:4 - at least that's the simplest explanation I've found so far.
     

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