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  • Can someone help me

    I dont get this rejection.
    http://www.jetphotos.net/viewreject_b.php?id=1492552
    Rejected for undersharpened and JPEG compresion artefacts. Now to me this photo looks sharp on my screen. If i sharpen it any more i get jagged edges. And can someone please explain this JPEG compression? I dont get it. I reduce my images in several steps rather than one big step and i apply no compression to my files yet i get this rejection.

  • #2
    Originally posted by ollieholmes
    I dont get this rejection.
    http://www.jetphotos.net/viewreject_b.php?id=1492552
    Rejected for undersharpened and JPEG compresion artefacts. Now to me this photo looks sharp on my screen. If i sharpen it any more i get jagged edges. And can someone please explain this JPEG compression? I dont get it. I reduce my images in several steps rather than one big step and i apply no compression to my files yet i get this rejection.
    The photo looks soft here on the screen.... How much steps do you reduce your images in?

    Ruben

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    • #3
      The filesize is very small with just 210kb. Might have used a bad jpeg setting by accident ?
      My photo editing guide - updated and improved Feb. 2010
      My Nikon D100,D200,D300, D800, D7200 basic spotting settings guide
      ACIG - the best resource for military aviation information

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      • #4
        Originally posted by ollieholmes
        I dont get it. I reduce my images in several steps rather than one big step .
        The worst thing you can do, every time you resize there is an element of compression/quality loss. To much compression also gives the effect of areas that are soft along with areas that are sharper all in the same image. Either crop & resize at the begining of your workflow or resize just before you save it as jpg.

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        • #5
          Originally posted by mrk25
          The worst thing you can do, every time you resize there is an element of compression/quality loss. To much compression also gives the effect of areas that are soft along with areas that are sharper all in the same image. Either crop & resize at the begining of your workflow or resize just before you save it as jpg.
          With these the compression was done straight after converting from RAW to jpeg where i then make my tweaks and then save.

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          • #6
            Originally posted by seahawk
            The filesize is very small with just 210kb. Might have used a bad jpeg setting by accident ?
            I thought 210kbs was not bad for files from a D50. Ive uploaded files smaller than that before.

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            • #7
              Originally posted by Thebuzu
              The photo looks soft here on the screen.... How much steps do you reduce your images in?

              Ruben
              3 steps, down to 2000 pixels, 1500 and then finaly 1024.

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              • #8
                Well, 210kb is a usula size for an upload wiht an aircraft in the sky, with such a background it seems small to me.
                My photo editing guide - updated and improved Feb. 2010
                My Nikon D100,D200,D300, D800, D7200 basic spotting settings guide
                ACIG - the best resource for military aviation information

                Comment


                • #9
                  Ollie,

                  There's been a discussion on the other site about sizing in stages. There are some people who resize in stages and some who resize in one step. Trouble is, no-one seems to be able to come up with a definitive reason why ?

                  Personally, my workflow goes like this....

                  1. Equalise the original and clean up dustspots
                  ( although I am tending to do this after step three sometimes.
                  Depends how much sky is in in the pic )

                  2. Level the original.

                  3. Crop and resize at the same time i.e. set the crop tool to 1200 x 800.

                  4. Set the histogram levels.

                  5. Adjust contrast.

                  6. Use shadow/highlight very sparingly, most times not at all
                  ( Awaiting a curves tutorial !! ).
                  If the aircraft has a sky or different contrast background then I create a
                  layer before shadow/highlight use and delete the sky to avoid "Haloes".

                  7. Overall sharpening as required. Use layers to remove jaggies as they
                  appear and selective sharpening where required.


                  I don't think I've ever had a .jpg compression reject using this style of workflow.
                  If it 'ain't broken........ Don't try to mend it !

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                  • #10
                    Not a bad shot......but with a shutter speed probably at less than 1/125 there is a bit of blur working against you.
                    It is worthwhile in cases like this to see the original........we have no idea what has been done in post processing.
                    However after looking at a few of your photos, I am guessing that you are underexposing your shots, leading to an increase in noise levels that is your problem here.
                    My contribution to JetPhotos

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                    • #11
                      The compression artifacts are in the sky mainly towards the right hand side. This may also contribute to overall softness of the pic. When a pic is too overly compressed, the compression algorithms have to throw something away to get to the required compression level. Different compression algorithms achieve this in different ways, however one thing the usually happens is the high frequency components in the picture are thrown out. The High frequency components are responsible for the detail in a picture. Hence the softness.

                      Also note the distortions around the wheels of the plane. So much data has had to be discarded that the wheel are very soft and in fact loose the sharp edge that defines the wheels.

                      This is a bit of a simplification, but in this case it looks like the Softness and compression go hand in hand.
                      Last edited by Billsville; 2007-07-04, 09:57.

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                      • #12
                        Originally posted by Billsville
                        The compression artifacts are in the sky mainly towards the right hand side. This may also contribute to overall softness of the pic. When a pic is too overly compressed, the compression algorithms have to throw something away to get to the required compression level. Different compression algorithms achieve this in different ways, however one thing the usually happens is the high frequency components in the picture are thrown out. The High frequency components are responsible for the detail in a picture. Hence the softness.

                        Also note the distortions around the wheels of the plane. So much data has had to be discarded that the wheel are very soft and in fact loose the sharp edge that defines the wheels.

                        This is a bit of a simplification, but in this case it looks like the Softness and compression go hand in hand.
                        Thank you. Now things make sense to me.

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                        • #13
                          Someone asked for the orgional so here it is, all i have done is reduced it to 1024 pixels wide in one step.

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                          • #14
                            How do you selectively sharpen?

                            Enough said? This one I'd love to learn!


                            Dave Brook
                            Cambridge, Ontario

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                            • #15
                              That "original"...at 74kb is not much help Oliver...



                              You are only going to solve your problem by taking time and checking all your settings (camera & editing).
                              I notice all your Exif is stripped from your photos. I thought I read that you use PS7.........don't know if that is responsible or other software that you use......for example, how do you upload from your camera to computer.
                              My contribution to JetPhotos

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