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curious2021
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Thanks for the reply. I’m confused though. My reading of the Moire pattern is that it’s caused by two overlapping patterns which produce multiple slits that the light passes through, diffracts and interferes, producing an interference pattern? So Moire patterns are really interference patterns? From what you’ve said though, it sounds like I’ve read that article wrong?sophiecentaur said:Diffraction patterns and Moiré patterns have a lot in common and it can be difficult to distinguish between them. @Motore has assumed that the patterns are Moiré and they may well be (so not optical diffraction) but there are colours around those fringes, which implies there's some wavelength dependence. You will probably see some of that patterning in diffuse lighting (which doesn't support visible diffraction fringing well. There may be 'beats' between the thread spacing and the regular variation of colours along the threads themselves.
I suggest it's a bit of both because some of the fringes have coloured edges. But also there is clear colouration in the irregularities elsewhere in the picture.
If you want to see diffraction patterns through fabric then look at distant street lights (pinpoints of light) and you can get all sorts of repeated dot patterns. See this link for some pretty patterns, including curtain diffraction.
They are the result of the interaction of two patterns which, with a different hat on, is the same as optical interference where two wave patterns add together in different ways in different places. I guess you could say that there is interference in both cases but diffraction only in the optical case.curious2021 said:So Moire patterns are really interference patterns?
Hah - I spotted it but not sure if I can actually explain it!curious2021 said:great spot on the color too.
[Edit: important to know I'm talking about my Pentax SDSLR]. There is no blur filter (Anti-aliasing) but, if you are taking critical pictures where the moiré is noticeable, the sensor is vibrated (same motors used as for dust elimination and star tracking). Cool eh?Orthoceras said:In high resolution cameras the color moire effect is less conspicuous, and no blur filter is needed.
I think in this case that one pattern is the curtains (mesh with the threds) and the other is the camera sensor. (I see @Orthoceras beat me to it)curious2021 said:My reading of the Moire pattern is that it’s caused by two overlapping patterns
It looks to me like the lines of threads and the pattern on the threads themselves. This can be resolved if the OP saw the patterns before he took the picture.Motore said:I think in this case that one pattern is the curtains (mesh with the threds) and the other is the camera sensor. (I see @Orthoceras beat me to it)
https://photographylife.com/what-is-moire
A diffraction pattern is a visual representation of the interference pattern created when a wave, such as light or sound, passes through an obstacle or slit. It is characterized by alternating light and dark bands, with the brightest band corresponding to the direction of the wave's strongest intensity.
A diffraction pattern is created when a wave encounters an obstacle or slit that is comparable in size to the wavelength of the wave. As the wave passes through the obstacle, it diffracts or bends around the edges, resulting in interference patterns that can be observed.
The appearance of a diffraction pattern is affected by several factors, including the size and shape of the obstacle or slit, the wavelength of the wave, and the distance between the obstacle and the observation point. Additionally, the type of wave and the medium through which it is traveling can also impact the diffraction pattern.
A diffraction pattern is different from a reflection or refraction pattern in that it is created by the bending of a wave around an obstacle, rather than its reflection or refraction through a medium. Diffraction patterns also exhibit a distinct interference pattern, whereas reflection and refraction patterns do not.
Diffraction patterns have a wide range of applications in various fields, including optics, acoustics, and electronics. They are used in the design of optical instruments, such as microscopes and telescopes, and in the analysis of crystal structures in materials science. Diffraction patterns also play a crucial role in the study of sound waves and in the development of technologies such as ultrasound and sonar.