Archived posting to the Leica Users Group, 1998/11/24
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Erwin wrote : Well the most elaborate testing equipment lab is the owe used by PopPhoto. Still most Luggers would not even care to consider the results and Eric wrote recently that the PopPhoto results are questionable. ####### At 07:16 24/11/98 -0600, Eric wrote : Yes, it's questionable, when they only test one sample out of the thousands of examples that were made of that particular lens. Such an impression by a test of that sort is, to say the least, questionable. It may actually test out way better than the average. My courses in statistics makes me way too cynical on this point I'm sure. >-- > >Eric Welch ############## With the modern manufacturing process (quality control and laser centering), one lens is a good sample among a population.So the method is not questionable (from a statistical point of view, that's another story : cf. theory of small samples). You may have a lens slightly over or under the mean, that's all. But there are neither "bad" lenses nor "super"-lenses.One exception :with zoom lenses made by independent manufacturers, you may have decentered (?) elements.(On that point Sigma lenses had a bad reputation in the past). Your argument, if it was true, would mean that the test of a lens is useful for that lens and solely for that lens. So testing and publishing the results, whatever the testing method, including Erwin's one, would be useless, wouldn't it ?. Dominique Pellissier Dominique Pellissier