Archived posting to the Leica Users Group, 2000/02/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>>>Classifications are based on dividing lines, and so PopPhoto and CdI will tell you that a resolution of 30 l/mm ot CdI: an MTF of 30%) qualifies as good and a resolution of 31 l/mm (31%) as very good. Now this is ridiculous, No one can see the difference between the 30 and 31 lines or the 30 and 31% contrast transfer. But it is a logical consequence of their methodology and therefore it is not a good one. As I do not know when reading the CdI qualification if the difference of 'good' versus 'very good' is a small borderline difference or a big one (high end and low end of both classes) I am at a loss how to interpret the results<<< So true. This has long been one of my objections too. With _POP's_ "SQF" you can see that a 94.9 will not get an "A" whereas a 95.1 will!! This fine a distinction is almost certainly finer than sample variation (with most makes of lenses) and probably finer than degree of error in the testing eqipment (? I don't know this for sure). And yet it results in different classifications. - --Mike