Archived posting to the Leica Users Group, 1998/04/23
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]<< But it is still more impossible for a consumer (and you are and I am a consumer)to know if a product is good or not. >> Dominique, you are correct that it is very important for us as comsumers to get as much information as possible regarding lenses, before we purchase them. There are many sources of information. However, so sources are not reliable. Other sources contain information that must be taken with a grain of salt. Other sources have useful informtion, but often that information must be interpreted. Erwin was correct in noting that it is important to understand the undelying basis for the tests, such as CDI's tests. An example is the test series by Popular Photography on the three Leica lenses in 1994 50 1.4, 35 1.4 and 75 1.4). All three tested very poorly at the largest two apertures. The test results were horrible at 1.4 and 2.0. However, at the middle apertures the lenses were absolutely outstanding. Knowing how Popular Photography tests their lenses helps explain this. Popular Photography is very "biased" toward flat field lenses with no curvature of field. All three of these Leica lenses have substantial curvature of field. This makes their test results very bad at the widest apertures. One must look critically at the test reports in order to understand they meaningfully. Tom Shea