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 ...
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 ...
- 341
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 ...
- 21.7k
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. ...
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 ...
- 176k
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 ...
- 39.4k
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 ...
- 33.2k
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 – ...
- 39.4k
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 ...
- 23.4k
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 ...
- 5,525
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 ...
- 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 ...
- 111
Only top scored, non community-wiki answers of a minimum length are eligible