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  • Problems with JPG compression artefacts/over processed/bad postprocessing

    Evening all,

    Wonder if anyone can help? My airliner success rate needs to improve. Quite a number are rejected for JPG compression artefacts (see United 767 photo below) and a couple for over processed/bad processing (see Flybe Dash below - looking back this was a poor photo to send anyway).

    Any tips gratefully received.

    Many thanks,

    Ian.

    6891778


    6900517

  • #2
    In my experience using an outdated version of Camera RAW (if you're shooting with a Canon camera) can cause artefacts. Did you get a new camera? I also get them if I edit a photo in Lightroom then save it in Photoshop, but the picture is fine if I export from Lightroom directly. I don't know your editing workflow, but try poking around the settings when saving. I assume the jpg quality is set to 100%.

    The Flybe photo looks like it was masked badly or something, the plane has a sort of glow around it if you equalize the image.

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    • #3
      Originally posted by iansomjen View Post
      Evening all,

      Wonder if anyone can help? My airliner success rate needs to improve. Quite a number are rejected for JPG compression artefacts (see United 767 photo below) and a couple for over processed/bad processing (see Flybe Dash below - looking back this was a poor photo to send anyway).

      Any tips gratefully received.

      Many thanks,

      Ian.

      6891778


      6900517
      First check your save settings. That's most likely where your problems with compression begin. THe UA file size is only 128k, which is less than half what I would expect for an image of that resolution, and quite indicative of high compression.

      Comment


      • #4
        Hi chaps.

        Thanks for your help - much appreciated. I actually don't use a photo editing package just the one that comes with the laptop. I usually change the exposure (if needed) and clarity. I resize the photo using Paint and to fit the jet photos requirements I change the pixels to horizontal 1261 and vertical 861. I guess there must be a better way to edit than this.


        I have a Canon 7D and alternate between AV F11 and TV640 when shooting airliners. Still in the learning process.


        Thanks, Ian.

        Comment


        • #5
          Originally posted by iansomjen View Post
          Hi chaps.

          I actually don't use a photo editing package just the one that comes with the laptop. I usually change the exposure (if needed) and clarity. I resize the photo using Paint and to fit the jet photos requirements I change the pixels to horizontal 1261 and vertical 861. I guess there must be a better way to edit than this.
          Ian, consider getting a more powerful editing software. If you are shooting JPEG (I hope you are) there is a free software that will do everything you need and more, it's called GIMP. Even resizing a digital image can be a tricky thing and I would definitely trust GIMP more to do that than Paint. Ditto for saving at maximum quality to avoid JPEG compression. Whatever program you choose, don't be intimidated by the myriad functions, you would only need to get the hang of a few to get started.

          I have a Canon 7D and alternate between AV F11 and TV640 when shooting airliners.
          If I may ask, why do you set aperture to f/11? Unless you have a very unusual lens you should be able to go wider, let's say to f/8, without losing anything and keeping shutter speeds up. I'm specifically referring to photographing aircraft on approach with a telephoto lens, not night shots or extreme close ups etc.

          Alex

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          • #6
            Hi Alex,

            Many thanks for your time and help. Will check GIMP.

            Best wishes

            Ian.

            Comment


            • #7
              Hi Alex,

              Have downloaded Gimp - thank you. How do you resize/save them to match with Jet Photo requirements?

              Many thanks,

              Ian.

              Comment


              • #8
                Originally posted by iansomjen View Post
                Hi Alex,

                Have downloaded Gimp - thank you. How do you resize/save them to match with Jet Photo requirements?

                Many thanks,

                Ian.
                Hi Ian,

                the tool to use is "Scale Image". Through the drop downs:

                Image > Scale Image...

                In the scale screen:
                1. pick and interpolation method. I recommend Lanzcos3 (this could be a whole separate discussion...), but most importantly don't set it to "none".
                2. type in the width you want if it's a typical landscape image. Let's say 1200 pixels or whatever you like. No need to enter the height, the ratio will be maintained.
                3. Hit "Scale"

                When you go to save the file, use File > Export As

                1. Put whatever file name and location you'd like but make sure it ends in ".JPG" (if you want a jpeg to upload to JP for instance)
                2. Hit "Export"

                - Another dialog window opens now that GIMP knows you want a jpeg, this is where you set the quality to max to avoid the most fundamental kinds of jpeg compression issues:

                3. Set Quality to 100

                Bonus - you can open "Advanced Options" to tinker with some more stuff:

                3a) I prefer to turn off subsampling (i.e. set to 4:4:4) to hypothetically maximize quality
                3b) I set smoothing to 0.00, this is not necessarily the only way to go, but as far as I know this is little more than a last minute blurring to get rid of certain kinds of artefacts, so this has the potential to mess with the workflow. If the image being worked on is already a jpeg then I see this as kind of pointless, as you are already OK with the sharpness of the edges etc. by the time you're saving a final version
                * the other Advanced Options don't affect image quality

                4. Hit "Export" and you're done.

                More info on the Export As tool here (but we've already covered the essentials): https://en.wikibooks.org/wiki/GIMP/Saving_as_JPEG

                The other key tools that I would recommend you explore when you have the chance are:

                - Curves (Colors > Curves) - this isn't the easiest tool to use, but it does the job of several other tools and is worth knowing. That knowledge would transfer to any other image editing program. Remember you can use it in 2-3 passes instead of trying to get the full effect in one go. Example: first pass could be an S curve or something like it for contrast and a second pass could be a final trimming of the edges of the histogram
                - Rotate (Tools > Transform Tools > Rotate) - easy
                - Crop (Tools > Transform Tools > Crop) - easy
                - Scale (already covered)
                - Unsharp Mask (Legacy) - another powerful tool that will take time to get right and can be used in any image editor. The Threshold setting is what makes this worthwhile. Normally used to sharpen but can also be used to adjust contrast, especially locally (large radius, low strength). Did I mention Threshold?
                - Export As (already covered)

                Have fun!

                Alex

                Comment


                • #9
                  Hi Alex,
                  Thank you so much for your time - you are a gent. Will give it a whirl tomorrow.

                  Best wishes,
                  Ian.

                  Comment


                  • #10
                    Morning Alex,

                    Had a little tinker with GIMP this morning. I couldn't find this setting - 1. pick and interpolation method. I recommend Lanzcos3 Any thoughts?


                    Many thanks,

                    Ian.

                    Comment


                    • #11
                      Originally posted by iansomjen View Post
                      Morning Alex,

                      Had a little tinker with GIMP this morning. I couldn't find this setting - 1. pick and interpolation method. I recommend Lanzcos3 Any thoughts?


                      Many thanks,

                      Ian.
                      Oops, I forgot that the latest version of GIMP doesn't have Lanzcos3 anymore. It was replaced with LoHalo and NoHalo, which I don't know enough about. I can, however, vouch for the Cubic interpolation, it also produces good results.

                      Alex

                      Comment


                      • #12
                        Thanks Alex. Appreciate your help.

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