49 votes
Accepted

What causes these white, squiggly lines in my photos?

This image shows a rather long exposure. The image in general is very dark, but a few spots are light. Probably some reflection on shiny surfaces like the door knob, the sink and the tap. If you ...
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  • 622
46 votes
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Taken a picture of my monitor while spinning in circles - why is it distorted?

The reflection on the screen tells me you used a flash. The flash only lasts a very short time (at most 1/200 of a second), while the shutter was probably open for a much longer time (maybe 1/30 of a ...
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  • 985
39 votes
Accepted

Why do photos of digital screens turn out the way they do?

This is moiré. It occurs because a screen is actually a grid of squares that are being used to make the image. When it ends up trying to be mapped to another grid of pixels (either by being captured ...
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  • 34.4k
35 votes
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What causes these inconsistent dark bands in some of my photos from an indoor event?

The variability you are seeing in your photos is due to the way many types of lighting convert alternating current into light. Although they look constant and steady state to our eyes, in reality they ...
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  • 167k
28 votes
Accepted

What could be the reason for these block-like artefacts in the blue sky?

I would suggest that it might actually be a sensor fault (or firmware bug). My reason for suspecting this rather than JPEG artefacts or banding is that the surrounding sky has exactly the same ...
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  • 13.2k
25 votes

Why do I see this yellow color shift at high ISOs and fast shutter speeds?

I think "several fluorescent fixtures that I use to light my studio" is the key here. I'm guessing that the very high ISOs are accompanied by very short shutter speeds. Fluorescent lights cycle, and ...
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  • 140k
22 votes

What could be the reason for these block-like artefacts in the blue sky?

These look like JPEG compression artifacts, possibly caused by picking a lower-quality setting in the camera settings. On many cameras there's e.g. a Fine JPEG mode and a SuperFine mode, or something ...
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  • 5,012
21 votes
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What could cause this white speck in a blue sky?

This looks like a stuck/hot pixel in the sensor. Due to the demosaicing algorithm, it has affected not just one pixel in the output image but also four diagonally adjacent pixels. I would be willing ...
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  • 13.2k
19 votes
Accepted

Solve unwanted white "waves" and "Pacman squares" in low-light picture - post using Google Photos

This is known as "banding". Dark parts in the picture have a small range of values (in a JPG, you only have 256 values per color), when you lighten them, you increase the gap between consecutive ...
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  • 16.1k
17 votes

How can I avoid circular banding artifacts in clear skies when de-noising?

I actually wouldn't describe what you're seeing as a halo artifact. It seems to me to be posterization — there just aren't enough tones to smoothly represent the gradient of the sky. It just happens ...
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  • 140k
17 votes
Accepted

How do I take a photo so the moon doesn't have bright "rays"?

The "ray" effect is known as sunstar. There are 2 conditions to achieve sunstars : use a narrow aperture (like f/16). point camera to small and bright light source. You achieved that effect very ...
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  • 710
14 votes
Accepted

What causes these streaked rays from light sources?

In my opinion that "flare" is caused by a dirty lens. I'm guessing you attempted to clean it, by using a wipe, but failed to properly clean it, which is why the flare has directionality. Try using a ...
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  • 20.7k
12 votes

How can I avoid green flare on my sunrise photos?

tl; dr. Blend a "panorama" from only slightly rotated exposures and make sure no flare is included in the final result. It's not possible to optically remove this type of flare when shooting into the ...
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  • 2,843
12 votes

Why do I get dark horizontal lines (stripes or bands) in bad lighting with my Fuji X-T1?

These lines are very likely there because of the frequency at which your light flickers. This is most notably the case with fluorescent lighting or led lighting, especially when you dim the light. Led ...
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  • 121
11 votes
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What is the blue circle in this moon image?

I agree with what Hermann said, but have a different answer as to how to avoid this. Expose properly. Notice that the blue smudge is much dimmer than the moon, which is so bright that it is totally ...
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11 votes

How can I avoid green flare on my sunrise photos?

I have done three things in the past to deal with this. Compose the photo in such a way that the lens flare is attractive... that's a great choice for your example above because the sun is IN the ...
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  • 1,075
11 votes

What could cause this visible artifact which seems to a be a glowing inverse of something outside of the frame overlayed on this photograph?

What you are seeing in the photo is a specific type of lens flare known as ghosting. It is an inverted and reversed reflection of the brightest highlights of the scene. If you were to draw an x and y ...
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  • 167k
11 votes
Accepted

What is this shadow in my photo?

It is either subject motion or camera motion. 1/80 second is pretty slow for human subjects not making a specific effort to be still. It is also pretty slow to use hand held if you are going to pixel ...
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  • 167k
11 votes

What caused some of the bright, diffuse areas of sky in some of the Apollo images from the moon?

It looks like lens flare. It is an internal reflection inside the lens. It is caused by off axis light allowed to fall on the front surface if the lens from outside the field of view. For an example ...
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  • 167k
11 votes
Accepted

How to edit photograph to remove flashes of light / glow / glare?

When an image contains pure white (#fff or values RGB 255/255/255) - we refer to this as "blown" or "blown out". There is nothing you can do to alter these pixels to gain lost detail. For example, I'...
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  • 20.3k
11 votes

What is causing the "bright spot" artifact in my picture?

This artifact falls under the heading of flare / ghost image. It is caused by internal reflections. The camera lens is a complex array of multiple polished glass lens elements. Some elements are ...
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10 votes

Why do photos of digital screens turn out the way they do?

As your existing (+1) answer says, it's a Moiré pattern. But you see it particularly when the image is scaled. You don't say what does the scaling, but I'm guessing you're just zooming the display, ...
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  • 3,602
10 votes
Accepted

What is "veiling glare"? How does it affect my photos, and how can I avoid it?

Veiling glare is light that's not intended to be part of the image, per se, but ends up on the recording medium (film or sensor) anyway. It's caused by reflections and scattering of light by optical ...
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  • 140k
9 votes
Accepted

Why does this satellite image of an airplane in motion show red, green, and blue bands with strange artifacts?

AJ is correct here. What you are seeing is the result of motion blur as both the satellite and the aircraft are in motion relative to the ground (the desired target of the photo). Those pretty ...
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  • 106
9 votes
Accepted

Strange pattern in picture

These are demosaicing artefacts introduced when converting the image from the bayer array that the sensor records into an image with complete colour information for each pixel. In an effort to ...
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  • 621
9 votes
Accepted

What causes blue artifacts when viewing an image in Camera Raw or Lightroom?

The blue and red highlights in Adobe Camera Raw or Adobe Lightroom are called the Shadow/Highlight clipping warnings. They are indications of shadow or highlight areas that are lacking detail, meaning ...
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9 votes

What caused the strange "wave X" lines in the out of focus background area in this photo?

It strongly appears you were shooting through a chain-link fence, chicken wire, or something else with a diamond-shaped pattern. Here is where I think the fence or wire would be (apologies for my ...
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  • 31k
8 votes
Accepted

Why am I am seeing rings (banding) instead of smooth graduation in my sunrise pictures?

The first thing you must realize is that what you are seeing on your monitor is not the raw file. What you are seeing is an 8-bit demosaiced preview conversion of the raw file created by Photoshop (or ...
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  • 167k
8 votes

What is this bright squarish pattern that I'm getting in long exposure images?

It is a hot pixel. The reason it makes that little checkerboard shaped mark is because of the way digital cameras use single luminance values for each pixel to create color information by filtering ...
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  • 167k
8 votes

Why is the bottom of this image over-exposed?

My bet is on the same thing you guess — light reflected from the diffuser bouncing around badly. This is especially likely if you've tipped the flash to point the diffuser dome forward, as I've seen ...
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