20 votes

What is this called and what causes it? Bright highlights along contrasting edges

Looks like a processing effect to me. Part of a sharpening or local contrast effect - particularly unsharp masking. Mobile telephones - and to a lesser extent in-camera processed jpegs - are devils ...
ItWasLikeThatWhenIGotHere's user avatar
10 votes

What causes color artifacts on the strings while shooting guitars?

We've just figured it out. As Ben Rudgers correctly pointed out, the problem is caused by the lack of anti-aliasing filter on the Hasselblad sensor. It produces much sharper pictures, but with a lot ...
Michal Trnka's user avatar
9 votes

Easy tool to correct geometry of photographed document

Look like Gimp, which was born on Linux but also has versions for Windows and OSX these days. If your problem is to fix something like this: Then you just start the Perspective tool, set it to ...
xenoid's user avatar
  • 21.1k
7 votes

What is this called and what causes it? Bright highlights along contrasting edges

Coming from an image compression background, I would refer to this as one kind of "ringing artefact". The culprit is generally that the image has been processed in the frequency domain. ...
SE - stop firing the good guys's user avatar
7 votes

In photo taken with a prime lens, what is the cause of the "zoomed" bokeh appearance?

This is just an educated guess that I've never tested or seen specifically tested with lenses that have been highly corrected for field curvature and astigmatism, which are intimately related. Most ...
Michael C's user avatar
  • 175k
3 votes

How many optical aberration types are there in lenses? And what are they?

Spherical Aberration: Rays coming from near the axis of the lens arrive at the focal plane a form a vertex a specific distance downstream. Rays from the margins of the lens form a vertex at a ...
Alan Marcus's user avatar
  • 38.9k
2 votes
Accepted

What's the relationship between chromatic aberration, ISO and long-exposure noise reduction?

There are two components of noise that most noise reduction algorithms reduce: luminance and chrominance. Luminance is the kind of noise that makes the shadows look grainy due to varying brightness ...
Michael C's user avatar
  • 175k
2 votes

What is behind this symmetric coma like effect, and literally odd-ball bokeh, in a triplet lens?

What is the actual combination of aberrations at play here, The "spinning top" bokeh near the edges appears to be tangential astigmatism. Because the bokeh balls don't change their "width" (i.e., the ...
scottbb's user avatar
  • 32.6k
2 votes

What is lens astigmatism?

The task of the lens-maker is to fabricate a lens that projects a faithful image. Only one glass lens element will project an image, but that image is flawed. This lens will be fashioned convex – ...
Alan Marcus's user avatar
  • 38.9k
1 vote
Accepted

Compensate aberration to improve the quality of a surveillance camera

You can't 'rescue' what has already been thrown away. It looks like the sharpening/smoothing/HDR algorithm employed by the camera's software is trying to iron out every imperfection, to such a degree ...
Tetsujin's user avatar
  • 23.2k
1 vote

Compensate aberration to improve the quality of a surveillance camera

If there is a thick glass placed at an angle in front of the lens it will cause double image (same size and shifted to one side) because of glass producing an internal shifted reflection. It can then ...
Euri Pinhollow's user avatar
1 vote

What is this called and what causes it? Bright highlights along contrasting edges

This sort of effect can also come from how digital camera sensors work. For most sensors used in phones and digital cameras, each pixel can only sense brightness. These individual pixel sensors have a ...
Aaron's user avatar
  • 111
1 vote
Accepted

How does using more spherical lenses compensate for spherical aberration?

Playing around in a ray optics simulator I think I figured out how additional spherical lenses can compensate for spherical aberration. Since spherical aberration is caused by rays further away from ...
JDN's user avatar
  • 111
1 vote

Is it a bad idea to activate lens-corrections in camera, when also use lens-correction in Lightroom?

LR does not apply lens correction to JPEGs, only to RAWs (unless forced to do so). Enable the correction on both: the camera will give you corrected JPEGs when you shoot JPEGs, LR will give you ...
FarO's user avatar
  • 1,329

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