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What is a 500W HD camera and how can it be 500 million pixels?
Simon:
come on children, settle down.
magic:
--- Quote from: Someone on November 09, 2021, 09:10:39 pm ---
--- Quote from: Zero999 on November 09, 2021, 12:15:34 pm ---How small can the pixels be? I would have thought that diffraction would limit the smallest pixel size to half the wavelength of the longest wavelength of light it needs to respond to. Assuming that would be 700nm, the pixels can be no smaller than 350nm, so a 500M pixel CCD would need to be larger than 350×10-9√(500×106) = 7.83mm by 7.83mm.
--- End quote ---
Light needs some depth to be absorbed as there are boundary/surface effects in the materials. Add some other material to keep light from spilling into neighbouring pixels and it gets hard to make things smaller than the 700nm pixels currently state of the art:
https://www.techinsights.com/blog/part-2-pixel-scaling-and-scaling-enablers
--- End quote ---
The effect of diffraction is actually determined by the F-number of the lens alone.
https://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
Below 1µ pixel size you hit a point of diminishing returns where something may perhaps be recovered with heavy processing if the lens is on the fast side f/1~f/2.
Nokia 808 was said to use the diffraction from its f/2.4 lens as the antialias filter. Pixel pitch was 1.4µ.
Zero999:
--- Quote from: magic on November 10, 2021, 07:00:12 pm ---
--- Quote from: Someone on November 09, 2021, 09:10:39 pm ---
--- Quote from: Zero999 on November 09, 2021, 12:15:34 pm ---How small can the pixels be? I would have thought that diffraction would limit the smallest pixel size to half the wavelength of the longest wavelength of light it needs to respond to. Assuming that would be 700nm, the pixels can be no smaller than 350nm, so a 500M pixel CCD would need to be larger than 350×10-9√(500×106) = 7.83mm by 7.83mm.
--- End quote ---
Light needs some depth to be absorbed as there are boundary/surface effects in the materials. Add some other material to keep light from spilling into neighbouring pixels and it gets hard to make things smaller than the 700nm pixels currently state of the art:
https://www.techinsights.com/blog/part-2-pixel-scaling-and-scaling-enablers
--- End quote ---
The effect of diffraction is actually determined by the F-number of the lens alone.
https://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
Below 1µ pixel size you hit a point of diminishing returns where something may perhaps be recovered with heavy processing if the lens is on the fast side f/1~f/2.
Nokia 808 was said to use the diffraction from its f/2.4 lens as the antialias filter. Pixel pitch was 1.4µ.
--- End quote ---
Great, so a 500M pixel full colour CCD would need to be nearly 45mm by 45mm and cost a huge amount of money.
TimFox:
Not video, but this reminds me of the time I was photographing cityscapes in downtown Chicago with my 8x10 view camera and Ektachrome E100G sheet film, and a tourist asked me how many megapixels I had.
A rough mental computation, and I replied "about 500". Given the roughly 80 lp/mm resolution of the film, this was about right, since the film area was 51,600 mm2. (Assuming 1 lp = 2 pixels.)
Circlotron:
I wish there was an easy way to use a flatbed scanner as a camera. ~150 megapixels for everybody!
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