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This article is missing a huge factor: aperture. If you go higher than f/11 the debris will start to get much more visible. All of the pictures in here are at f
by seaish 8y ago
This article is missing a huge factor: aperture. If you go higher than f/11 the debris will start to get much more visible. All of the pictures in here are at f/5.6 or less.
Each pixel basically takes a weighted average of all the light that travels from a pixel-sized area in the world to the lens. As the picture with the dark area shows, this makes the debris form a dark area over a large part of the image. As the f number increases, the weighting gets stronger until 100% of it is a single line from scene to lens to pixel. At this theoretical f/infinity, you'll see all the lens's imperfections in perfect detail since the camera is essentially a pinhole.
- Laforet 8y agoYou'd run into diffraction limit for any reasonable pixel size long before the pinhole diameter gets smaller than the wavelength of visible light. The rest of your comment I fully agree with.
- Nition 8y agoAlso fairly rare to be shooting at higher than F/11 anyway, isn't it?
- petepete 8y agoIn normal situations yes. On occasions where you want to maximise DoF and focus stacking isn't an option (say macro shots of moving insects) it's a useful approach. The DoF when shooting macro can be fractions of a millimetre.
- brudgers 8y agoMy understanding is that the diffraction limit correlates with "sensor" size. f11 is about the limit for the APS-C sensors common in DSLR's. f16 is usable for 35mm film and full frame. With large format film cameras, f64 is usable, e.g. Group f64. https://en.wikipedia.org/wiki/Group_f/64 https://en.wikipedia.org/wiki/Group_f/64 There is a diffraction limit calculator at the bottom of this page, https://www.cambridgeincolour.com/tutorials/diffraction-photography.htm https://www.cambridgeincolour.com/tutorials/diffraction-phot...
- ackbar03 8y agoThis sounds extremely specific. Do you know where I can find a formula describing this weighting mechanism or modeling light and camera and lenses in general? Thanks!
- starky 8y agoA good companion to this article is the one by Lensrentals where they actually show what happens when the lens is stopped down, particularly the effect on flare. https://www.lensrentals.com/blog/2008/10/front-element-scratches/ https://www.lensrentals.com/blog/2008/10/front-element-scrat...