----- Original Message ----- From: "Mishka" Subject: Re: ye olde film v D debate, a bit long
> finest lens resolve far more than that. > even on film. > difraction limited lens can get >100 lp/mm at at f5.6, 50% mtf. > so the 40 lpmm is mostly limitation of the film, afaik. > > Lens tests are universally (and erroneously) done using a high contrast (50:1 or higher) test chart. This gives totally useless information for the pictorial photographer, since lens resolution is directly tied to subject contrast. If a lens is tested at the more reasonable 1.6:1 toc, then more useful resolution information is made available. Note, if all you want the lens for is shooting resolution charts, then go hard, and your 100 lp/mm number is probably as good a guess as any, and film is not the limiting factor, as Tech Pan will resolve over 200lp/mm at 1000:1. If you want to know what the lens will really do in a pictorial situation, toss the USAF chart, it's isn't worth the paper it's printed on. The best resolution test I have found is distant tree branches against the sky on a still day. William Robb
