>From the dictionary: acutance : (noun) the sharpness of a photographic or printed image. • a measure of this. ORIGIN 1950s: from acute + -ance .
As I use the terms, acutance differs from sharpness in that I use sharpness to refer to the perception of detail where I use acutance as the measure of detail. Resolution is a more specific term, usually calculated rather than observed but it can be either. If resolution is "observed", then it is a synonym for acutance. Example: A 6 Mpixel sensor of size 16x24 mm has 2000x3000 photosites, so its spatial resolution is nominally about 63 line pairs per mm to first order calculation (half the number of photosites per mm). However, given the addition of an antialiasing filter and other factors like the algorithm used in the conversion of captured data to a viewable form, the number of line pairs per mm that can be obtained usually runs about 10-20% less, so the acutance of that sensor is likely in the 47-52 l...@mm range. That sensor assembly can produce images which display a lot of sharpness in perceptual terms ... meaning the images have good edge definition (a product of contrast differentials over short spatial dimensions ...) to our eye but that actually don't have an enormous amount of resolution. Make sense? On Fri, Dec 31, 2010 at 9:11 AM, Boris Liberman <bori...@gmail.com> wrote: > Hi! > > I kind of know what contrast, resolution, sharpness is. But what does > "acutance" mean? > > Thanks in advance. > > Boris > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. > -- Godfrey godfreydigiorgi.posterous.com -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
