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Diopter/Magnifier Together?


novice9

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Is it possible to use a 1.4 magnifier and a diopter to correct my lousy vision at the same time?

 

I can answer your question, but i need to know what your prescription is. How lousy is your vision :D and, about how old are you?

 

Rick

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i'm 42. i have an astigmatism, quite pronounced in one eye and very minor in the other, but i'm also near sighted as of the past 3 or 4 years. i've worn glasses since i was 4, but in the last few years i take them off when i read.

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well, i would prefer to shoot with right eye (since i'm a right) but don't because that's the eye with the severe astigmatism. tomorrow when i get to work i'll post my eye script, hopefully that will tell you what you need to know. thanks very much, i really appreciate the help!

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well, i would prefer to shoot with right eye (since i'm a right) but don't because that's the eye with the severe astigmatism. tomorrow when i get to work i'll post my eye script, hopefully that will tell you what you need to know. thanks very much, i really appreciate the help!

 

I have the identical problem - so I shoot with my left eye, corrected with a -1.0 diopter correction lens as I have -2.0 prescription glasses. I have both Leica magnifiers - but only will use them for 135 mm or may be a 90 mm lens. For the 75 mm and 50 mm lenses I find attaching the correction lens to the M9 viewfinder directly works better for me because of better contrast and light. Other folks on this forum have pointed out similar experiences in the past. I also find myself cleaning the M9 viewfinder glass a bit as I have not mastered yet not to touch the M9 right there.

 

Goof luck with your choices.

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And beware! The correction lens for the magnifier needs another strength than the diopter lens for the camera!

 

Thanks for the pointer. Is there a general rule as well.

 

Comparing my prescription glasses to the viewfinder correction lens I had to lower the diopter by 1 to get the correction lens working correctly.

 

So, what then is a typical adjustment for the correction lens on the magnifier?

 

Thanks for your help.

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If you had to lower it by 1.0 it sounds like the ideal value for you would have been 0.75, which does not exist. Thus you might just get away with the same diopter, as the difference is -0.5.

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So my eye perscription is as follows:

 

dv-o.d.: +2.00 (sph); - 3.00 (cyl); 180 (axis)

dv-o.s: -1.25 (sph); - .50 (cyl); 20 (axis)

nv-o.s./o.d. (ie, the are the same) +1.25 (sph); then the dr. wrote add the two +1.25's (o.d. and o.s.) together for the cylindrical value.

 

I use my left eye to focus the camera.

 

Any help on what diopter correction to use would be very helpful.

 

Thanks.

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Yes, I get this, but I very recently was my opthamologist and don't plan on going again for a couple of years. So if there is a reasonable way to determine w/o going to the doc office (which it sounded like from one of the other posters), that is what i am trying to achieve here.

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So my eye perscription is as follows:

 

dv-o.d.: +2.00 (sph); - 3.00 (cyl); 180 (axis)

dv-o.s: -1.25 (sph); - .50 (cyl); 20 (axis)

nv-o.s./o.d. (ie, the are the same) +1.25 (sph); then the dr. wrote add the two +1.25's (o.d. and o.s.) together for the cylindrical value.

 

I use my left eye to focus the camera.

 

Any help on what diopter correction to use would be very helpful.

 

Thanks.

 

Hi novice9. Thanks for giving me some numbers so I can answer your question. This is going to take some time to explain, so if you want to skip all of this, just use your right eye and follow jaapv's post above and skip what I am going to write.

 

First of all, you are right that your right eye has too much astigmatism to give a clear enough image for focusing a range finder accurately without glasses. So, for now, let's put it aside and talk about your left eye.

 

Your left eye has only 0.50 diopters of astigmatic correction, that's good. You will not need to have this corrected with a cylinder lens, the amount is too small. But, we can convert it to its spherical equivalent, which is -0.25. That is the amount we need to add to your spherical correction to get your total spherical correction. [-1.25 + -0.25 = -1.50]

 

So, on first look it would seem that you need a -1.50 lens for your camera. But, there are a couple of wrinkles in the process that you need to think about.

 

First, the range finder in the M already has -0.50 incorporated into the viewfinder. I actually measured the viewfinder with a radiuscope and found the exact amount to be -0.67. Anyway, we can call it -50 for this discussion. So you would think that this would mean you only -1.00 diopters of correction. And that might be true for you. Except, the next wrinkle in this is accommodation, your eye's ability to focus.

 

Second, accommodation of your eye. If, you are young enough you can accommodate (focus). By about age 45 you need help with this and people start finding the need for reading glasses... I'll finish in a few ...have to go back to work. :(

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Yes, I get this, but I very recently was my opthamologist and don't plan on going again for a couple of years. So if there is a reasonable way to determine w/o going to the doc office (which it sounded like from one of the other posters), that is what i am trying to achieve here.

Go to the chemist and try it with the rack of throw-away reading glasses.

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