Archived posting to the Leica Users Group, 1999/12/01
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>A 50mm lens at f/1.4 focused at 10 feet has from 9'7" to 10'5" in focus. A 100mm lens at f/1.4 focused at 20 >feet (exact same image size on the film as the 50mm example), >Jim > > No, by magnification, what I mean is that a 50mm showing the subject at the > plane of focus of 1/2 life size is going to be X inches from the subject. A > 100mm macro lens at 1/2 life size is going to be 2X the distance. >Eric These statement are in themselves approximations. You can determine that with basic high school trigonometry. But those who are more comortable gleaning their beliefs from voices of authority can refer to page 52 of the New Leica R8 sales brochure by Leica Camera AG, Germany. (what better authority could there be :) ) Angle of view of the 50mm Summicron R - 45 degrees, Angle of view of the 100mm Apo-Macro-Elmarit-R - 25 degrees. 45 = 2 times 25 (approximately). > To say that it is an approximation shows a lack of > understanding of the nature of optics.