Archived posting to the Leica Users Group, 2000/08/05
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]In a message dated 8/5/00 3:53:45 PM Eastern Daylight Time, henningw@archiphoto.com writes: << That's the real test of the effective relative aperture, or 't-stop'. >> For more on T-stops or T-numbers and related topics, see the Focal Encyclopedia of Photography. In the 3rd Edition (1993), check p. 791. I was looking for the name Cooke, which I remember as the name of the optical firm which developed lenses calibrated in T-stops. There may have been others unknown to me. Joe Sobel