We have so many more millimeters horizontally and vertically 2,500 lines / 24 mm = 100 l/mm.) Thus I can seeĪ loss of sharpness in the examples below starting at f/8, with a theoreticalĬan get away with small apertures like f/64 because our film is soīig. Requires both a light and a dark pixel, the D200 resolves about 2,500 The anti-alias filter in all cameras and the fact that a line pair (The D200 has about 3,800 pixels across 24mm, or 160 MTF is similar to a frequency response curve. resolution curve is called Modulation Transferįunction (MTF). Resolution, and about 50% contrast at half that resolution. This is because the contrast falls at the lower resolutions Sharpness if you stop a lens down to f/16 which can resolve 100 l/mm.
![diffraction refraction diffraction refraction](http://www.pas.rochester.edu/~blackman/ast104/diffraction.gif)
If you haveĪ system which only resolves 50 l/mm, you can still see a loss of Is reduced as the resolution approaches these figures. Levels at small apertures, because the resolution limits are so lowĪre the resolutions at which contrast falls to zero. Lenses reach this level at large apertures. A lens this good is called "diffraction limited." Few Maximum resolution is limited by f/number. Know the limiting resolution is defined by the diameter of the Airyĭisc which is defined by the f/number, and astronomers and spy satelliteĭesigners know that angular resolution is defined by the diameterĭiffraction is accurately predicted by both ray and wave See MTF Curves for an even better technical explanation.ĭiffraction is caused by light rays bending around sharp edges. See also this site with many more illustrations. See my Zenitar 16mm Fisheye review, where I explicitly show a crappy lens completely obliterating the performance of a Nikon 10.5mm DX fisheye due to diffraction and its different effects at each aperture. Window or through a small f/stop and you get the equivalent of a Your eyes - that's diffraction! Look or photograph through a screen You look or photograph through small holes you get diffraction. Through diffusion cloth or window screens.
![diffraction refraction diffraction refraction](https://i.ytimg.com/vi/E9UJjdlTQQI/maxresdefault.jpg)
The same softening effect happens when photographing Is a loss of sharpness or resolution caused by photographing I use Adorama, Amazon, eBay, Ritz, B&H, Calumet, J&R and ScanCafe.