What is the name of this distortion or artifact? This is usually found in smartphone cameras, Nikon and Sony point-and-shoot cameras. This is not found in Canon point-and-shoot cameras, in Canon point-and-shoot cameras, instead of this distortion or artifact, a speckled pattern is seen.

When a photo taken with those cameras is seen in full resolution on a normal sized monitor, you can notice a kind of haziness, splotches and smudges around edges and lines in the photo, wherever they may be, not towards to edges of the frame. Is this due to sensor or lens, what is the name of such distortion or artifact?

The distortion/artifact I'm talking about is visible in the feathers of duck in this photo I've included a crop of the part that shows the distortion I am talking about:

enter image description here

In case the site prevents hotlinking, you can see the duck's photo in this review: https://www.photographyblog.com/reviews/nikon_coolpix_a900_review (Don't forget to click it to see in full resolution)

Here is another image:

enter image description here

Click on it see it full resolution, what is the distortion called which is everywhere on the house? What is the distortion/artifact called which makes the bushes before the house appear like green blobs?

Image of the house taken form DP review of P950.

  • I've added a crop of the distortion I think you are talking about. Please edit your question to include the correct part of the photo if the current crop shows something else than you are referring to. Sep 13, 2021 at 11:03
  • @SaaruLindestøkke The distortion/artifact I'm talking about is visible where ever feathers are present, it is not just confined to the area you cropped but thanks for illustrating this feature. Sep 13, 2021 at 11:13
  • The artefacting in the house pic reminds me of Why do my photos have such poor quality? - the aggressive noise removal/smoothing/artefacting is so bad as to look like someone put it through a painting emulator - i.stack.imgur.com/A9sBL.png
    – Tetsujin
    Sep 13, 2021 at 15:53
  • these images are - technical term - "fine" and "good enough" Sep 13, 2021 at 22:37
  • @aaaaasaysreinstateMonica I hardly consider them to be "fine" or "good enough". Sep 14, 2021 at 7:36

3 Answers 3


The issue is already addressed in the review you are linking to and there, they call it image smoothing. It is the noise reduction algorithm, which works so agressively that image details are removed in the assumption that the details are noise.

To quote from the test:

Noise isn’t too problematic, but you can often see some severe image smoothing which gives a painterly effect when shooting in low light.

Your description in the question is a little bit vague, but I assume this is what you are talking about.

  • It also not impossible that the duck was shuffling its feathers and that we see is partially a motion blur.
    – xenoid
    Sep 13, 2021 at 11:35
  • @xenoid Very unlikely. If it was motion blur, you should be able to make out a directional smear. The other high ISO sample images in the review also have the same artifact visible on non-moving subjects.
    – jarnbjo
    Sep 13, 2021 at 11:58
  • So there isn't any well established word for that? Is it due to sensor or lens? But why isn't this visible in Canon images? Sep 13, 2021 at 12:45
  • I've added another image, can you look at it and tell me. Sep 13, 2021 at 13:13
  • 1
    @bypassrestrictions It is caused by the software in the camera in post-processing. The issue with the house in your second image is something else. Those artifacts are caused by heat shimmer, perhaps in combination with the previous 'image smoothing' problem. But if you have a new question, you should also ask a new question instead of adding new topics to an existing question.
    – jarnbjo
    Sep 13, 2021 at 13:36

Diffraction (Latin to bend backwards) is a phenomenon that changes the path of radiant energy.

Light rays from objects generally travel to your eyes following a straight-line path. Often as these rays travel they are forces to pass through regions of changing air density. Hot air expands and thus has less density whereas cooler air had more density. The speed of light is a constant in the vacuum of space however, as light traverse’s transparent substances is slows depending on density.

Light, on its way to your location encounters patches of air with differing temperature. Hot air expands and thus has less density whereas cooler air has more density. Additionally, the boundaries between these patches reflect.

The effect is called heat haze. This is the stuff of shimmering, haze, and mirage. This is also why the stars appear to twinkle. Additionally, dust in the air scatters light waves impairing the blue of the sky.

  • The duck is too close for heat haze to be a relevant problem.
    – jarnbjo
    Sep 13, 2021 at 17:48
  • 1
    I think you mean mirages not marriages. :-) Sep 13, 2021 at 19:56
  • I don't think that can explained by atmospheric elements, because in telescope it isn't that exaggerated. Sep 14, 2021 at 7:37
  • The second image is definitely affected by atmospheric movement between the camera and the house and surrounding trees. Some people call it heat shimmering, because it is caused by the ground and bodies of water absorbing the sun's energy and then heating the air directly above them, causing variations in the density of the air based on temperature.
    – Michael C
    Sep 15, 2021 at 6:29

The duck picture (link to full size image) is shot at ISO 800 which is pretty high for a 1/2.3" sensor. One would expect the image to be very noisy if noise reduction is disabled. The "artifacts" you see is due to aggressive noise reduction. Noise reduction blurs detail and is very apparent on complex patterns such as the duck's feather pattern.

The distorted house is due to heat waves (refraction through different temperature regions). The following image shows really bad heat wave refraction of a Thunderbirds flyby, probably around 1 mile (1.6km) distance. Air temperature was around 89°F (32°C). Heat wave issues ("seeing" is a term used by astronomers to describe optical atmospheric disturbances) are a big problem for astronomers as well as photographers.


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