DoF may not exist...

Started 3 months ago | Discussions thread
JimKasson
MOD JimKasson Forum Pro • Posts: 35,338
Re: Another approach...

Erik Kaffehr wrote:

We can see that mst good lenses reach optimum sharpness at f/4. The only factor reducing sharpness when stopping down is diffraction.

The airy radius is 1.22 * N * Lambda. Assuming Lambda being 0.55 micron, we would get the airy radius where diffraction cames into role to be 1.22 * 4 * 0.55 -> 2.7 microns.

The corresponding diameter is 5.4 microns.

So, it may make some sense to use around 5-6 microns as CoC good lenses at optimal aperture.

I consider that to pessimistic.

https://blog.kasson.com/the-last-word/blur-circle-size-estimation-with-encircled-energy/

http://web.ipac.caltech.edu/staff/fmasci/home/astro_refs/PSFtheory.pdf

So your 5.4 um diffraction diameter would be about 3.9 um for EED70.

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