Archived posting to the Leica Users Group, 2001/02/25
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> Here's why I don't like optical bench testing of UV filters. > Lets say you > test a lens with a filter and you get a test value of 7.9 (with > filter) and > 9.2 (without a filter) In whatever units you are measuring on the optical > bench. You may conclude that without a filter you get a value 1.3 more > than with and therefore you shouldn't use UV filters to protect a lens. > > But, what means 1.3? Can this be seen in an 8x10 print? 11x14? 24x36? > What are the minimum test value differences before a certain enlargement > size at a certain viewing distance becomes visible to the human eye? I plan on translating the numbers I get into real usable information. I will get resolution numbers, like without UV is 80 lp/mm without and with is 78 lp/mm. I can translate that into what size enlargement that will have an effect, or on what films you will even be able to record that difference at all etc. I'll start from the front and work my way back. If anything, I will have a very well documented analysis from image to print/scan/projection.