Lars
Active member
I've wondered for a while now about the conventional wisdom re diffraction limit in lenses.
Diffraction limit is ususally measured as the point where the MTF falls below a certain percentage.
However, as I understand it, this does not mean a complete loss of information but rather a softening of the image, a loss of local contrast.
In theory, it should then be possible to recover detail finer than the stated diffraction limit, by applying a local contrast enhancement such as highpass filtering. Compare to the 1-dimensional application in sound - a muffled recording can still contain rich treble details which a highpass filter can recover (as long as the higher frequencies have not been completely clipped).
The application here is of course higher resolution image sensors, specifically if it makes sense to use sensors approaching 30+ megapixels limited by 35mm format, or if diffraction limitations eliminate the benefit of higher resolution.
Lars
Diffraction limit is ususally measured as the point where the MTF falls below a certain percentage.
However, as I understand it, this does not mean a complete loss of information but rather a softening of the image, a loss of local contrast.
In theory, it should then be possible to recover detail finer than the stated diffraction limit, by applying a local contrast enhancement such as highpass filtering. Compare to the 1-dimensional application in sound - a muffled recording can still contain rich treble details which a highpass filter can recover (as long as the higher frequencies have not been completely clipped).
The application here is of course higher resolution image sensors, specifically if it makes sense to use sensors approaching 30+ megapixels limited by 35mm format, or if diffraction limitations eliminate the benefit of higher resolution.
Lars