Archived posting to the Leica Users Group, 2002/06/21
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>This past day or so, someone answered a question about the use of diopter >correction lenses with an M. The response said that you should match the >READING prescription..... could I please get a confirmation of this fact? Only true in very specific situations. Probably not true for you if you are way over 40. Then your problems is likely to be that your eye can not focus sharp at different viewing distances, just at one limited range of distances. That range may well be further away than infinity or shorter than reading distance. I am short sighted on one eye and far sighted on the other. When I was young, I used single strength glasses that corrected one eye in one direction and the other in the other direction to something like a medium distance. My eyes then did the fine tuning to reading distance or to infinity as required by the situation. With age, my eyes were no longer capable of too much fine tuning, so I started wearing bifocals. Now bifocals are no good for me as they leave the middle range out of focus if your eyes get 'inflexible' and I have started using glasses with continously variable focus. They are great, but the sharp field is a bit narrow for reading over a long period of time, so I also have reading glasses. Reading glasses, and M diopter correction lenses at reading glass strength, are great for focusing, but only at reading distance. Both are worthless for focusing at mid range and infinity. Glasses with continously variable focus are great for focusing M cameras at all distances. The normal problems with focusing with glasses prevail, like not being able to see the whole viewfinder area. Unfortunately there are no variable focus correction lenses for M cameras as the camera viewfinder requires you to look through the center of the lens while the variable focus lenses require you to look at different sections of the lenses for correctly focusing distant and near objects. Chris > >I have tried several times to get my Hassy with a diopter adjustment lens, >without success... I was trying to match my long distance perscription.... >With that luck, I never tried to get my Leica to work correctly through my >glasses using add on diopters..... > >I happened to be looking through a Voigtlander finder, and needed to move my >eye to the point that I was looking through the reading perscription to get >all in focus.... This brought up my question about trying to match the >reading perscription to get my eyeballs to be in focus through one of these >"fancy" Leica cameras..... > >Frank Filippone...........over 40, way over 40. >red735i@earthlink.net > > >-- >To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html - -- Christer Almqvist D 20255 Hamburg and / or F 50590 Regnéville sur Mer http://www.almqvist.net/chris/new - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html