Preventing anomalies

Discussion in 'Seeking Critique' started by G&R, Feb 11, 2021.

  1. G&R


    The small brown bird was no more than 10cm long.

    There are artefacts, particularly around the beak (bright green line underneath / black shadow burn above), that I do not know how to prevent pre-process or remove post-process. Do you think using a flash would have helped?


    Camera Model: SAMSUNG GX10 Focal Length: 30000/100 Exposure Time: 1/180 F-Number: 9.9 ISO Speed Ratings: 140
  2. Removing post process ... try magnifying and then using your clone tool, delicately and with precision, to stamp out the offending areas. You also might work with both your dodge and burn tools.
    G&R likes this.
  3. You might also try a chromatic aberration correction. Not sure if it will help, but the pattern is similar to what we see with CA.
  4. G&R


    I agree, particularly as there appears to be an aberration around the branches. However, the CA tool (at least in Gimp) applies only to blue/red, and neither of those bands are out of alignment. My finding is that magenta and green are misaligned. Magenta can be simply filtered without loss and the green is more problematic. Other pictures of this subject have a clear beak, but all have a magenta/green aberration around the branches that may have wind movement.

    It appears to me that the beak moved during exposure because if it was slightly higher then there would be foreground black above, and background green below - which is what the image shows. However, the lack of motion blur defies my understanding of how sensors work (unless the sensor has a refresh rate?).

    I was testing IBIS at the time - could this be related?
    Last edited: Feb 12, 2021
  5. G&R


    After airbrush above the beak and desaturated underneath - point fix, but similar aberrations appear elsewhere in the photo. Any critique of methods used or camera settings? I was about 3-4m away from the subject.

  6. I'm not sure, but I tend to agree with @G&R that 'movement' could play a role in the CA. It looks to me as if the 'vertical CA' on the horizontal branches is stronger than any horizontal CA on the vertical branches.

    If the branches and the bird were moving (wind and/or head motion), then a shutter speed of 1/180 isn't all that fast at 300 mm (on a crop sensor). I read that the SAMSUNG GX10 has 'sensor-based image stabilization' and I'm not quite sure what effect (if any) this might have had at this shutter speed.

    Software like Adobe's Lightroom and Photoshop have 'Lens correction' filters which correct for things including CA. They might help in this case (RAW files) and they might not.

    The only other alternative is cloning/patch or painting sampled colors into precisely selected areas.
    G&R likes this.
  7. G&R


    I have just realised is that the Sigma DG lens delivers a much warmer colour tone. Furthermore, when I add a skylight filter to a smaller Sigma DL the two lenses produce almost identical colours.

    Could the Sigma DG's features be responsible for the CA in the photo?
  8. I'm primarily a bird and wildlife photographer and learned not to try to rescue weak images. In this one, the bird is not in the clear, the head angle is away from the camera and there is no eye-light. As you shoot, keep these flaws in mind and try to overcome them. It takes time to be in position and wait for things to align, but that's how it's done. I often spend hours to get one shot.

    No flash is needed. Take lots and lots of shots.

    [​IMG]Welcome To My Studio Mr. Finch... by David Stephens, on Flickr
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  9. Sure, ok, but that wasn't the OP's question. It was how he got and what to do about halo and discoloration. So, it might be the case that, on some future date, when the bird is in the clear, the head angle is more to your liking, and there is more eye-light, he will still be dealing with this technical issue about which he would like input and to be able to resolve.
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  10. He's trying to "process away" poor settings, etc. He's better off focusing on taking a decent picture to start with. Why is he adjusting this image? It belongs in the Trash. Maybe he should post this to Digital Darkroom Forum.
  11. Hopefully, to learn. I’ve spent plenty of time over the years on some of my rejects, learning sometimes that I have something I didn’t think I had, but more often learning I couldn’t “save” it but that my time was still well spent learning post processing skills that I eventually put to use toward keepers even though I learned them on rejects. I’ve actually grown quite a bit by not simply immediately tossing my rejects but by spending quality time with them. That’s helped me understand what I’m looking for even though I don’t always find it and helped me hone my vision. Some of my rejects have pointed me in new directions I might not have thought of but only because I studied and worked with them enough to get something out of them. A lot of things that in the surface may seem like a waste of time, if approached with openness can turn out to be of value. To each their own.
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  12. William Michael

    William Michael Moderator Staff Member

    Noted that the OP has raised several questions - initially these questions were concerning only post processing, however there are quite a few additional questions which have been asked.

    Apropos ‘camera settings’

    EXIF reveals F5.6 (not F/9.9) and Spot Metering Mode, Aperture Priority no EC applied; Shutter Speed and ISO as per OP

    I see symptoms of leading edge blur, (not restricted only to the beak), which leads me to the same opinion that there is high chance of Subject Movement.

    I'd guess that the lens, at 300mm, would be at or close to wide open at F/5.6. Additionally the shot having been pulled: F/5.6 @ 1/180s @ ISO140, is reckoning a scene at about EV = 12, however, the use of Spot Metering, combined with Av Priority with no EC applied raises the question of what part of the scene was being metered: assumed the middle and that no exposure lock and re-frame technique was applied. Hence a plausible line of thought would be Spot Metering was on dark brown area of bird.

    Shutter speed too slow resulting in Subject Motion Blur - 1/500s to 1/1000s advised
    Aberrations exacerbated by using lens wide open
    Spot Metering (combined with a semi automatic camera mode - i.e. Av Priority) and no EC, resulted in (general) overexposure: exacerbating Aberrations


    >Lens Filters will likely exacerbate Aberrations

    >Lighting appears generally soft (whilst assuming that there is underexposure), the skilled use of a flash could harden up that lighting, however there would be many other considerations including, but not limited to the link between these two main considerations:
    . Shutter Speed chosen and Maximum Flash Sync available
    . Balancing the Ambient and Flash Exposures

    Be aware there are a multiplicity of considerations when one steps into the world of High Speed Flash Sync, and, whilst I’d foster your research in that area if you are keen to learn.

    Bottom line - My opinion is you need more flying hours under your belt at the moment and in that regard, taking lots of (disciplined) photos with a solid review process is what is required now. Therefore, as you gain more skills, you will be waiting longer before you release the shutter, and you will be setting up the shot in favourable light in the first instance: I think this advice echoes (perhaps explains/expands) David’s comments.


    Apropos ‘methods used’ - I concur with David’s strategy, that it serves little purpose to maintain a ‘method’ of addressing multiple imperfections by using post production in an attempt to correct same.

    That stated, I think it is not necessarily wasted time practicing Post Production methods on an Image which should be culled - indeed such images can make for good practice dummies: one key point is to learn to recognize which are practice dummy images and which are not.

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  13. I'm perhaps trying to move the OP toward the final solution before he's ready. The best way that a newbie can learn is by making mistakes, such as over sharpening and too slow shutter speed, etc.
  14. William Michael

    William Michael Moderator Staff Member

    Perhaps, but probably not - I think it is good for the OP to have received a forthright and articulate Brief of Outcome - it can make setting goals, easier.

    dcstep likes this.
  15. The photographer has a chance of determining an outcome or accepting one that’s pre-determined.

    The desired outcome may represent exactly the standard bird picture most bird photographer enthusiasts and professionals adhere to, found in high quality magazines and exhibitions, etc.

    There’s no saying, however, that someone photographing birds can’t choose a different, less familiar, less expected, and less stunning and sharp-eyed result, one that doesn’t offer the more standard eye light, head position, and clarity of background that may seem necessary to making a worthwhile photo of a bird.

    The OP may very well be going for a bird-perfect look and, if so, there are plenty of breathtaking examples he can learn to emulate as he waits for hours and hours in the field to get it just right.

    My critique was hinting at a crack in the door to something different, an outcome approached with a personal uniqueness of vision and perhaps even a flouting of norms rather than one tailored to already-determined standards.
  16. William Michael

    William Michael Moderator Staff Member

    That's one beauty of critiques, and more widely - forums: a place where a range of opinions are aired and options discussed.

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  17. G&R


    Indeed this is among the worst of the pictures taken while intentionally testing that IBIS was working, and I am keen to understand what went so wrong with this particular shot - its not an example of CA I have seen before. The magenta just seems erroneous. The colours above/below the beak also seem bizarre to me.

    As for whether is aesthetically pleasing or not - it is certainly not colourful, or interesting, or even a good illustration. It does however have artefacts that capture a reality of digital photography, which is an authenticity that so many photographers try to hide - I agree this one belongs in the trash beside many of Jackson Pollock paintings, but if the unique style can be mastered then who knows.. ;)
    Last edited: Feb 15, 2021
  18. Before you throw the Pollocks in the trash, send 'em to me. I'm a trashy kind o' guy! :)
  19. I can't find a review of your camera and lens; HOWEVER, I have seen CA much worse than this with Canon Rebels and Canon's bottom-rung lenses. I wouldn't be surprised if that lens isn't the guilty party. With the Canon issues, the photographer fixed the problem with a higher quality lens.
  20. William Michael

    William Michael Moderator Staff Member

    Specifically commenting on the causes of the Chromatic Aberration - I agree.

    What lens was used?

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