Archived posting to the Leica Users Group, 2000/05/18
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]According to my readings (Puts site below and Osterloh) an SLR with a split image focusing screen has an effective base of about 10mm with a 50/2 lens (Osterloh) while the 0.72 Ms have a base of 49.8mm. Alas I do not know how to calculate the improvement in focusing accuracy if one uses using a f1.0 lens. Perhaps some optical mathematician can helps us out? The 0.72 finder is more than capable of focusing the Nocti accurately; after all, it is only in the last few years that a high-mag finder has been available again. http://www.imx.nl/photosite/leica/m/bodies/rfaccuracy.html John Collier > From: "Takeshi Hashimoto" <hashimoto.takeshi@mailcity.com> > > On Thu, 18 May 2000 16:00:21 Peterson Arthur G NSSC wrote: >> >> I don't know, and so can only presume John is right, that the "M rangefinder >> is more accurate than a SLR at 50mm." But my question is this: given the >> fact that with an SLR one is actually looking through the lens at (almost >> always) full aperture, does it not then stand to reason that an SLR would be >> able to focus any lens, of whatever focal length and whatever maximum >> aperture, with sufficient accuracy for that particular lens? I'm not being >> argumentative, just asking what seems like a reasonable question. >> > > > But the accuracy of the M system is fixed by the width of the two viewfinder > ports. As the lens gets faster/longer, it (the margin of error) becomes too > great to focus within the DOF of the lens. In other words, with an f/1.0 lens, > the SLR is probably a little better. >