Archived posting to the Leica Users Group, 2006/06/17
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Tom, Good suggestions about looking at 135's. Yes, I don't have any issues focusing my 135's close or very far, but can get into trouble in the middle ranges when I reach for a 135 just to come closer not for any perspective reasons. Don don.dory@gmail.com On 6/17/06, Tom Schofield <leicaluvr@comcast.net> wrote: > > I presume that it is because they are using a lower mag viewfinder, > just like the 135mm not being usable on the 0.58 RF. As the > magnification goes down, RF accuracy goes down. The eyes on the 2.8 > increase magnification, and therefore focusing accuracy. The resale > value of the 135mm Elmarits with eyes may go up! > > Actually, if you read Erwin's article on RF focusing accuracy, the > most difficult for the rangefinder to focus are the 135mm's. The > longer focal length causes more focusing problems than the high > maximum aperture. The article is pretty technical, but basically the > RF baselength compared to the focusing distance makes middle- > distances to be the most challenging. Accurately focusing the 135mm > at 20 feet or so is more difficult than accurately focusing a > Noctilux or 75mm Summilux at 1M. The rangefinder is extremely > accurate at close distances, and loses accuracy as distance > increases. This apparently is more of an issue than the maximum > aperture reducing the DOF. > > Tom Schofield > > On Jun 17, 2006, at 5:43 AM, Don Dory wrote: > > > > I am still at a loss as to why the 135 APO can not be adapted but > > the 135 > > F2.8 can. The spectacles would help with focusing accuracy, but > > they can do > > the 75 Summilux which has an even narrower dof so it doesn't have > > anything > > to do with the rangefinder. The lens itself has the optics well > > forward of > > the mount so it is already teleocentric. > > > > Don > > don.dory@gmail.com > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >