Archived posting to the Leica Users Group, 2004/06/08
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Richard F. Man said the following on 6/7/2004 7:23 PM: > Sorry for picking this up after almost a month, but I tried this on a > few pictures and the effect is... "interesting." Usually I leave the > Radius at small amount and adjust the "Amount." This seems to change the > contrast and make the highlight "brighter" in addition to sharpening? > > So in layperson's term, exactly what does these settings do? I am not sure I can describe what it is doing -- in laypersons terms or otherwise. To help my understanding I made an image consisting of overlapping white, black, and gray squares, and applied the USM settings. As one would expect, it lightens light areas that are near to dark areas, with the level fading as one gets away from the darker area -- and vice versa. As someone else said on this list (or some other) -- "it enhances local contrast" It seems to be akin to the "edge effects" generated by developing without agitation. To see what effect is has on resolution, I downloaded the res chart form the Leica D2 from dpreview (see -- it is on topic). I applied the filter. I could find no evil effects. Overall, it looked like the lens/camera got better. On real images, it sometimes gives too much of a "halo" effect. Playing with the parameters can help. -- Clive http://clive/moss.net