You\'re making the assumption that micron size of the pixels is the determinant factor in the amount of diffraction being projected / captured. It\'s not. It\'s just a factor in whether you are containing the captured diffraction within a single given pixel or capturing it across multiple pixels. Slicing the sensor into 1,000,000,000 MP doesn\'t change the amount of diffraction ... it only changes how many pixels are making up the area of the diffraction (which will still be a constant compared to the projected image size capture by the whole sensor, and subsequent printing size @ magnification)
Certainly using smaller pixels will give the illusion of more diffraction on an individual pixel 100% basis comparison, but diffraction is a product of the optical projection, not how small you slice it.
Particularly if it were a lens optically designed for film with a more generous tolerance for angle of light. I imagine reducing pixel size on a digital sensor would definately cause more pronounced diffraction, possibly even earlier...
No....this has nothing to do with pixel shading....this has to do with diffraction of photons as light rays pass through an opening. It\'s a physical property of light and is well defined by simple equations that very clearly describe the reaction of light to an opening.
But different lenses degrade image quality differently as they are stopped down on the same system and sensor and that is what is commonly called diffraction even if technically incorrect by definition...
Granted I\'m talking about the best lenses around Rodenstock tech lenses which are of the highest resolving power of most lenses so diffraction along with small microns cause diffraction earlier . Now this was going against mostly 36 Mpx sensor which today at 42 like our Sonys the pixel pitch I think is 4.8 it has gotten closer . If we pair the new 50 1.4 Sony with something like a Rodenstock one may wonder how they would compare.
My point all along is on MF with best in class sensors and lenses I hit diffraction at F8. Today on just about every lens I tested on the Sony A7r II it hits at F11. Certainly a combination of factors but I know many MF shooters won\'t even go past F8. I sneaked in F11 without too much degradation but it still is their no question. I used 3 Cambo mount lenses from Rodenstock that had tilt and swing built into the mount so I can gain DOF with stopping down past F8. This is very common practice in MF digital. One reason we see many 3rd party adapters like Zoerk and such.
One thing I\'ve noticed is that the performance once into \"diffraction\" (f/16, f/22) is different for different lenses on the same camera with same sensor! I\'m not doubting clear definitions defined by equations but collecting and analyzing empirical evidence is Science too It seems we have multiple terms for \"diffraction\" one used in reviews and one defined in textbook. It also seems to imply there\'s alot more going on here that commonly gets referred as just \"diffraction\", it\'s complicated
Aperture size and f/stop are not the same thing.
A 400mm lens with an f-stop of f/4 has a (theoretical) aperture of 100mm
A 50mm lens with an f-stop of f/4 has a (theoretical) aperture of 12.5mm
100mm @ f/16 = 25mm
50mm @ f/16 = 3.125
Which (theoretical) aperture do you think will induce more diffraction (for a given format / distance of projection from the aperture to the film plane)?
My general rule of thumb is that when the math approaches the 4mm (theoretical for FF format) my concerns for diffraction are heightened.
Case in point, my 24mm TS-E starts showing around f/11, (maybe just past f/8 @ f/9).
At 24 / 8 = 3mm
At 24 / 16 = 1.5mm
All other things being considered, I will shoot my 24 @ f/11, but f/16 is definitely an \"Do I really want to do this?\" Knowing that 5.6 - 7.1 is really where I want to be.
Sep 20, 2016 at 10:50 PM
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It seems we have multiple terms for \"diffraction\" one used in reviews and one defined in textbook. It also seems to imply there\'s alot more going on here that commonly gets referred as just \"diffraction\", it\'s complicated