Yoricko Posted October 10, 2010 Share #1 Posted October 10, 2010 Advertisement (gone after registration) Yes, I did a search already. I am either mentally retarded, or just confused over the search results. I have a spherical equivalent of -1.125~ / -0.50 -1.25 both eyes (Near-sighted + Astigmatism). From what I know, the M diopter does not correct astigmatism. Also, the M cameras also has a -0.5 correction built-in set for 2 metres. Just to confirm, Does it work like prescription glasses? I do not normally wear spectacles (natural 'bokeh'), I do hope that with this device I can focus more precisely and accurately. Does it work that way? Do I need a -0.50 correction? Link to post Share on other sites More sharing options...
Advertisement Posted October 10, 2010 Posted October 10, 2010 Hi Yoricko, Take a look here M Diopter correction Confustion. I'm sure you'll find what you were looking for!
john_s Posted October 11, 2010 Share #2 Posted October 11, 2010 Yes, I did a search already. I am either mentally retarded, or just confused over the search results. I have a spherical equivalent of -1.125~ / -0.50 -1.25 both eyes (Near-sighted + Astigmatism). From what I know, the M diopter does not correct astigmatism. Also, the M cameras also has a -0.5 correction built-in set for 2 metres. Just to confirm, Does it work like prescription glasses? I do not normally wear spectacles (natural 'bokeh'), I do hope that with this device I can focus more precisely and accurately. Does it work that way? Do I need a -0.50 correction? The diopter built into the viewfinder is for someone with perfect distance vision. The standard diopters are to correct deviations from perfect sight. If you had a diopter made that had an astigmatism correction as well as ordinary spherical, it would have to be set at the correct rotational angle: then if you turned your camera 90 degrees to take a portrait, the astigmatism correction would be at right angles to its correct orientation and would make matters worse. So it's usual to ignore it, at least at first. What is the astigmatism correction for the eye you use for viewing (probably your right eye)? If it's -0.50 then you can probably ignore it. If it's-1.25 then the problem is more difficult. I suggest that you try -1.0. I think a bit too weak is better than a bit too strong. Am i reading you numbers correctly? I'm assuming -1.125 spherical for both eyes and the other numbers as astigmatism (cylindrical). Leica used to make a special diopter holder that would allow rotation of a diopter with strong astigmatism correction, but I think they are very rare. Link to post Share on other sites More sharing options...
juergen Posted October 11, 2010 Share #3 Posted October 11, 2010 From what I know, the M diopter does not correct astigmatism. Correct! Also, the M cameras also has a -0.5 correction built-in set for 2 metres. Correct Do I need a -0.50 correction? What you actually need is a -.75 correction. But since it does not exist I would recommend a -1.0 like John did. Please read HERE Juergen Link to post Share on other sites More sharing options...
tobey bilek Posted October 12, 2010 Share #4 Posted October 12, 2010 Ask your eye doctor what correction you would need for two feet without your glasses, spherical only. Drug store reading glasses try out. Walgreens has them. Can you not ignore astig as it is probably -.5? If you have to correct astigmatism, then keep your glasses on and try plus 1 and use top of bifocals or distance portion. I have no accomodation left and it works. I have astig in my shooting eye and use a DSLR with spherical correction variable both with and without glasses. The glasses solution and +1 diopter does not help much so I use built in spherical, no glasses, and ignore astig. I have computer glasses set to 24". This is the absolute best solution, problem being I can`t see distance and it is garbage for sightseeing. Solution being special camera glasses, 24" prescription for shooting eye and distance for other. This may drive you crazy. People who have cateract surgery often opt for it, one eye for close, one for far. Called monovision. They do not need reading glasses then. No perfect solution I am afraid. People can advise you, but they do not know how much accomodation you have so you are still taking a chance. My advice is based on none. Link to post Share on other sites More sharing options...
Yoricko Posted October 12, 2010 Author Share #5 Posted October 12, 2010 Its -0.5 (spherical) / -1.25 (cylindrical) for my left, and -0.5 (spherical) / -1.25 (cylindrical) for my right. Sorry for the confusing numbers. It's my astigmatism that is screwing me up. Read somewhere~ that the spherical equivalent calculation goes like (spherical + cylindrical/2) for astig above 0.5. That is where the number -1.125 came from. Link to post Share on other sites More sharing options...
john_s Posted October 13, 2010 Share #6 Posted October 13, 2010 1.25 units of cylindrical is not too bad. I still think that -1.0 (spherical) is going to be close to as good as you'll get with an off the shelf diopter. If you can get to a shop with various values in stock, you could try -0.5 as well. Link to post Share on other sites More sharing options...
mikebidwell Posted October 19, 2010 Share #7 Posted October 19, 2010 Advertisement (gone after registration) Like the original poster of this thread I find the matter of Diopter correction a little confusing. I have my M6 but wearing Varifocal spectacles I find its not too easy to focus . I've recently been to my optometrist who tells me that I need for my left eye (my focussing eye) is :- Sph: +3.0 - Cyl :- -0.25 - Axis 1.30. With an additon of +2.75 for reading Perhaps someone with more experience than I can cut through the technical jargon and tell me if I should get a Dioptre Correction Lens and if so what one please. Or any other suggestions would be greatfully received . Best wishes Mike Link to post Share on other sites More sharing options...
juergen Posted October 20, 2010 Share #8 Posted October 20, 2010 Mike, what you really need is a correction lens with + 3.5 diopters. But Leica unfortunately doesn't offer them with more than 3.0 diopters. Juergen Link to post Share on other sites More sharing options...
cbretteville Posted October 21, 2010 Share #9 Posted October 21, 2010 Leica used to sell a one that had no glass in it that you could have an optician fit a custom lens in. Not sure if that is still on the books. An email to Leica CS might be worth considering. Carl Link to post Share on other sites More sharing options...
Ulev Posted October 23, 2010 Share #10 Posted October 23, 2010 I had doubts myselve choosing the right value of correction. So I went to an optician ( not mine !) and did explain him that I was looking to buy a correction glass but I wasn't sure of the correction. So he measured my right eye, took a number of correction lenses and I did hold them in front of my Leica viewer, comparing one to another untill I did find the one that was comfortable to me. Ordered the Leica version and am a happy man now You could start asking for having the correction lens custom made but the Leica's size is too small (8mm) for them so then just ask to try their set of correction lenses. Rgds Ulev Link to post Share on other sites More sharing options...
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