Archived posting to the Leica Users Group, 1999/07/28
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi Mark, A T-stop does not represent a diameter. It's the effective transmission of the lens, that is the amount of light it let pass through it. Of course, it's a value always inferior to the F-stop. With a coated lens, the T-stop is about 98% of the F-stop. With an uncoated one, it can be as low as 30% depending on the lighting conditions. All the best. - -- Jean-Claude Berger (jcberger@jcberger.com) Systems and RDBMS consultant (MCSE) Lyon, France http://www.jcberger.com > I imagine a T stop would not represent a relationship > but a fixed diameter. > Mark Rabiner >