Archived posting to the Leica Users Group, 2001/11/01
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]B.D.: Something is wrong with the testing? I say live by the sword, die by it. People on this group are fascinated with MTF and even more fascinated with resolution testing. If that's the shorthand you want to use, you are going to find testing regimes were Leica comes out behind (note that Leica rarely publishes MTF figures). If the testing procedure is done consistently, and it makes some Leica lenses better, then you have to accept that some will do worse. Questioning the systemic considerations that lead to a low score for one lens questions the high scores too. When it comes down to it, no modern prime lens would ever do poorly enough, resolution-wise for it to be the drag on an optical system that ends in output: a "good print" is 6lp/mm on the negative (precisely why minilab prints can never be indicative of quality); scanning, 20lp/mm; printing b/w, 60lp/mm. The real problem is substandard image-processing equipment. MTF is a combination of resolution and contrast, and it is safe to assume that the floor for making "good" prints could be quite low. The upshot of this is that the only compelling reason to buy one particular lens over another, length and relative aperture being equal, is a difference in aberration characteristics, or the "fingerprint." - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html