![]() The featured photo on this post is also an example of diffraction, although of a slightly different nature. Note that the smaller opening causes a more significant effect: The two images below ( from Wikipedia) demonstrate the effects of diffraction with a large and small opening on a waveform passing through them. ![]() A larger opening leaves more of the wave minimally affected, while a smaller opening affects more of the wave. The part of the wave closest to the edge of the opening experiences the most drag, and “bends” considerably, propagating off at a different angle on the far side of the opening. In the case of an opening in a large obstacle (such as the aperture in a lens), the part of the wave near the center is able to pass through largely unscathed. “Drag” on a light wavefront increases as you get closer to the obstacle. For now, “drag” and “bending light” are simpler terms that describe the effect sufficiently enough.) You can read more about that here, if you wish. What actually happens is a much more complex topic that covers how diffraction is an intrinsic trait of electromagnetic waves. (NOTE: Drag and “bending” of light is not what actually happens. The simplest explanation I can offer as to why diffraction occurs would be that any obstacle introduces “drag”. The obstacle may be a small obstacle with space around it, or a large obstacle with only a slit or a hole through it through which the wave may pass. Any time a waveform encounters an obstacle, it will bend around that obstacle. Not just light, but the entire electromagnetic spectrum, as well as waves moving through water, sound waves, etc. Diffraction is a physical phenomena, a trait of waves as they move past an obstacle. Now that I have my own personal blog at my fingertips, I thought I would put down in a single, cohesive article, what the Diffraction Myth is, and debunk the myth with what I hope will be a relatively simple explanation backed up by some real-world examples and visual aids.īefore diving into what the diffraction myth is, it helps to fully understand what diffraction is. I have explained on many forums, on many occasions, the true nature of diffraction. ![]() Despite its broad recognition, diffraction is probably one of the most misunderstood things in photography. It is probably one of the more well-known technical aspects of photography, even by those who are not technically minded. If you have ever dug into the nature of light as it pertains to photography, or become involved in a discussion about how narrow (small) apertures adversely affect image quality, you have probably heard of diffraction. ![]()
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