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Thread: How to prevent JPG compression

  1. #1
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    Default How to prevent JPG compression

    Hello All
    Just wondering if anyone had any tips on how to prevent JPG Compression Aretfacts on a Canon?
    Cheers
    FBO

  2. #2
    Member jvdl's Avatar
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    Quote Originally Posted by FlyBoyOne View Post
    Hello All
    Just wondering if anyone had any tips on how to prevent JPG Compression on a Canon?
    Cheers
    FBO
    JPEG is a "lossy compression" format by definition and design. If you want to avoid compression, you must use RAW.

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    Member mahagonny's Avatar
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    It is not always true. Shooting in jpg is acceptable if you use a high format value. It certainly does not depend on the brand of the camera. Certainly shooting in RAW is a better method, but then this should also be saved in jpg to be accepted on JP.
    I use to process the RAW file and only at the end cut to 1200 x 800 px saving in jpg to the maximum size. If you use photoshop save the photo at the highest quality (12).
    Excuse my bad English.

  4. #4
    Junior Member meeshboi's Avatar
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    Yes, you shouldn't be shooting JPEG if your at least somewhat serious or wanting to edit your photos. Because JPEG is compressed, you cant adjust the exposure, colour, WB like you can do with RAW.

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    Quote Originally Posted by jvdl View Post
    JPEG is a "lossy compression" format by definition and design. If you want to avoid compression, you must use RAW.
    Totally wrong idea that I can not agree with you. JPEG Artefact is completely related to how you edit the photo and how you saved etc. No any single relation with JPEG/RAW format or Photo Machine brand.

    Quote Originally Posted by meeshboi View Post
    Yes, you shouldn't be shooting JPEG if your at least somewhat serious or wanting to edit your photos. Because JPEG is compressed, you cant adjust the exposure, colour, WB like you can do with RAW.
    Another wrong idea. If you know how to do it, you can also edit JPEG files like RAW editing. On the other hand; RAW is a system that should be preferred, but it is wrong to say ''annot be done'' in term of editing JPEG file

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    Quote Originally Posted by theaviationspotter View Post
    Totally wrong idea that I can not agree with you. JPEG Artefact is completely related to how you edit the photo and how you saved etc. No any single relation with JPEG/RAW format or Photo Machine brand.
    But nowhere did he mention artifacts, he asked how to avoid compression when shooting JPEGs.

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    Quote Originally Posted by theaviationspotter View Post
    JPEG Artefact is completely related to how you edit the photo and how you saved etc. No any single relation with JPEG/RAW format or Photo Machine brand.
    Very true.

    Also, it's not just that jpeg is lossy by definition that will cause you to see jpeg artefacts, it's also the fact it's 8 bit colour. Think of a picture that is 800 pixels tall that has blue sky of varying shades from top to bottom. There are only 256 shades of blue to choose from in 8 bit (and they won't all be present in that picture). If the sky is smooth enough you'll definitely have visible banding perpendicular to the direction of the gradient. Since you have to go to jpeg eventually, it wouldn't matter if you started with RAW or not in this case.

    How not to have jpeg compression artefacts?
    1. Save at max quality
    2. Take it easy on noise reduction in your processing
    ...not necessarily in that order!

    P.S. RAW definitely captures more data and lends itself to a broader scope of editing, no question about that IMO

    Regards,

    Alex

  8. #8
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    Quote Originally Posted by jvdl View Post
    But nowhere did he mention artifacts, he asked how to avoid compression when shooting JPEGs.
    You have to make a research about ''jpeg compression artefacts''

  9. #9
    Member jvdl's Avatar
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    Quote Originally Posted by theaviationspotter View Post
    You have to make a research about ''jpeg compression artefacts''
    No, preventing compression (i.e., lossless image capture) and preventing artifacts arising from excessive compression are two different topics. If the OP meant the latter, he should have been more specific.

  10. #10
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    Quote Originally Posted by FlyBoyOne View Post
    Hello All
    Just wondering if anyone had any tips on how to prevent JPG Compression on a Canon?
    Cheers
    FBO
    You need to be a little more specific. What kind of compression are you talking about? Have you received rejections for such recently?

    In general, there are three things that result in a 'compression' rejection at JP:

    1) actual highly compressed jpegs, i.e. not saved at maximum quality
    2) banding effects, often seen as Quebec Golf noted in skies with a color/brightness gradient
    3) 'pixel smearing' that you often see on images taken with cameras with small sensors (point and shoot/bridge cameras/cell phone camera)

    Each of those issues would be resolved in a different manner, so best to be as specific as possible with what you are asking.

  11. #11
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    It had been in there during the fourm that i was banging on about aretefacts, but so far thanks for the tip all

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    Quote Originally Posted by FlyBoyOne View Post
    It had been in there during the fourm that i was banging on about aretefacts, but so far thanks for the tip all
    I checked your rejections. The image of VH-DIC that was rejected May 11 suffers from compression due to the first reason I listed. It has nothing to do with the type of camera you use, you simply did not save/export the image at maximum quality. If you adjust that step in your workflow, the problem should be resolved.

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    I don't think shooting in RAW or Jpeg makes a difference as far as artifacts. I've done great things with Jpeg and I almost always shoot in Jpeg. For example, the following photo was shot in Jpeg: https://www.jetphotos.com/photo/9180296
    Always save at the maximum quality and that should fix the problem. If it doesn't there are ways to fix it in editing software that I believe will usually solve the problem. I've had a little more than 100 photos since my last compression rejection and about 90 of them were originally shot in Jpeg.

  14. #14
    Junior Member meeshboi's Avatar
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    Quote Originally Posted by Michael Rodeback View Post
    I don't think shooting in RAW or Jpeg makes a difference as far as artifacts. I've done great things with Jpeg and I almost always shoot in Jpeg. For example, the following photo was shot in Jpeg: https://www.jetphotos.com/photo/9180296
    Always save at the maximum quality and that should fix the problem. If it doesn't there are ways to fix it in editing software that I believe will usually solve the problem. I've had a little more than 100 photos since my last compression rejection and about 90 of them were originally shot in Jpeg.
    Shooting RAW or JPEG makes NO difference, I just don't see why people don't shoot RAW if they have the option, unless they either have a small buffer, not enough space or dont need to edit.

    But, each to their own opinion.

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