![]() That's a fact, but far too simplistic regarding diffraction. A greater number of pixels are then smaller pixels, a plus which better resolves any image detail (including that of diffraction). ![]() That "one pixel limit" notion comes from the fact that the pixel is the smallest dot that digital sampling can reproduce (specifically, two adjacent pixels, a dark and a bright one, is the least difference that can be properly resolved as an edge). There's a calculator below.įirst, a rant about imagining the size of one pixel increases some measure of limiting due to diffraction: That absolutely does Not mean we need larger pixels, which would just be less resolution too. The problem is the diffraction size, regardless of the pixel size. An Airy disk in even a good case like f/5.6 is larger than a typical pixel. And then yes, this Airy disk size can be computed in terms of our pixel's size, but which is just a comparison magnitude scale, and the pixel size as a measurement unit is NOT the problem. So we hear how our camera has an aperture limit if a lens aperture is stopped down to near the lens f/stop limit, and that part is valid, stopping down the aperture does increase the diffraction which does limit the resolution. The Airy disk is considered the limit on optical resolution, see SPIE for a study of the Rayleigh Criterion. Then it covers and blurs the true detail, reducing resolution. Stopping down the aperture makes the diffraction become larger. You ought to at least try stopping down in situations when you know it will help, and then will have the two pictures to choose from.Ī true point source when seen magnified (a star seen at high power in a telescope is the clearest example of diffraction) shows as a larger diffraction disk of concentric rings called an Airy disk ( see calculator below). The big point here is that sometimes stopping down for increased depth of field is desirable as an obviously better resolution result than the slight diffraction it causes (at least until it gets too great). Tiny pixels simply just better resolve any detail that is present, but pixels do not affect diffraction. It's not about the pixel, it's about the diffraction present. We know stopping down does increase Depth of Field, and yes, diffraction also becomes greater if stopping down too much, but sometimes it is incorrectly worded in terms of the issue being caused when diffraction becomes larger than our digital sensor's pixel size. We read on the internet how the resolution of our digital cameras can become "diffraction limited" as we stop down more.
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