Archived posting to the Leica Users Group, 1997/08/30
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Doc (teeth not eyes!) wrote: <snip> although my standard prescription is just a tad more than -3, there is also a correction for astigmatism. I find that by using a -5 diopter in the viewfinder I can see and focus perfectly, and have this correctinve lens in 35mm SLR and 6x7 SLR as well. <snip> If you have a mild amount of astigmatism, you can use the "spherical equivalent" by just adding more (-)minus correction. Usually, you divide the astigmatism correction amount by two and just lump that in with the spherical correction. This concept is also used when prescribing prescription lenses for dive masks. Its a compromise but it will work when you have a mild astigmatic correction. Other than my wife and photography, scuba diving is my other passion. Then I get to use my Nikonos V with a 15mm lens. No straight lines underwater so the 15mm works like magic. I'm jealous of Ted because he has a 15mm Leica R lens and knows how to use it. Maybe I could afford one if I stop feeding our two dogs... Richard - ---------------------- Richard Clompus, OD West Chester, PA, USA