In praise of AA filters

Started 11 months ago | Discussions thread
Lee Jay
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Re: Detail above Nyquist in MTF
In reply to rovingtim, 11 months ago

rovingtim wrote:

Lee Jay wrote:

rovingtim wrote:

Lee Jay wrote:

Lee Jay wrote:

Using the slanted line method of oversampling. That's s special case and no real detail can be found that way.

That has been my point all along. Software is 'creating' the appearance of detail over Nyquist in digital files.

Wrong.

So, what are those black lines in the image that are beyond Nyquist then?

Aliasing. Their spacial frequency is by-definition below Nyquist.

If that's true, then it suggests aliasing is destroying detail that would have otherwise been evident if the image had been guarded against aliasing. In other words, a file from sensor without an AA will have less real detail than a file from a comparable sensor with an AA filter.

That depends on the AA filter, but assuming a decent AA filter and sufficient detail in the scene and passed by the optics, that is true because aliasing corrupts real sampled detail.

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