Dioptre Value

[beoon]

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Would anybody out there with the correct knowledge be able to tell me from my prescription which dioptre lens would I need to buy to help with focusing (without wearing my varifocals).

 

Just to be clear I got my eyes tested last week and tried to ask the lady testing them, but I do not think she fully understood me, so I did not get an answer.

I cannot go to a Local dealer and try the different dioptres since the nearest Leica dealer to me is a long, long way away.

 

The prescription for my right eye is

Sph -2.50

Cyl +3.00

Axis 1.79

 

Thanks

 

Alan

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[juergen]

Alan,

 

in case of a Leica M read HERE

 

This mmeans in your case that you need a sherical correction lens with a value of -2.0, since the viewfinder of the M-camera is preset to -0,5

 

Cylinder and axis are not corrected

 

Juergen

[Shootist]

The simple answer is you need a diopter that correct your vision for a fixed distance of 7 feet (2 meters). The M rangefinder displays everything at around 7 feet (2 meters).

 

For me I wear + 1.5 to + 2 reading glasses, that is to read with and work on something close. For the M I use a + 1 diopter because that gives me correct vision at the 2 meter (7 foot) distance.

 

Go to a store that sells over the counter reading glasses and try different strengths until you find the one that give you the best, clearest, vision of what is displayed through the viewfinder. The get the closest M diopter offered erring on the lower side. In other words if you find that +1.75 reading glasses work the best get a +1.5 diopter.

[scsambrook]

Shootist's advice is good - best to try before you buy anything as expensive as a Leica correction lens. However, you may find the lack of a cylindrical correction a problem. Pehaps the best plan is to visit your optician - taking your camera! - to get his or her advice.

 

If you do need a lens made to your prescription, you will then have to get a lens holder for it. I have now emailed Leica service twice asking if this can be obtained but am still waiting a reply.

 

Good luck!

[juergen]

These holders (part number 042-253.008) seem to have long gone.

Even if you should be lucky to find one, it is apparently not easy to

find an optician who is able to grind such small lenses.

 

Another shortcoming is that a custom made lens can only be fitted

for portrait or landscape photography since it is not adjustable.

So if do both it is better to stay with specs.

 

Juergen

[ShotCapture]

I am not sure how to read my prescription. Here's what it looks like:

Spherical Distant O.D. -0.50

O.S. PL

ADD O.D. +2.50

O.S. +250

 

I'm leaving off cylindrical and axis.

Can you "translate" my prescription to a Leica M diopter? Thanks!

[Shootist]

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Another shortcoming is that a custom made lens can only be fitted

for portrait or landscape photography since it is not adjustable.

So if do both it is better to stay with specs.

 

Juergen

 

Not sure what you mean by that, bolded and underlined. Then why does the Leica diopter I use, a +1, work for ever type of photography, camera position and distance to the subject.

[juergen]

I am not sure how to read my prescription. Here's what it looks like:

Spherical Distant O.D. -0.50

O.S. PL

ADD O.D. +2.50

O.S. +250

 

I'm leaving off cylindrical and axis.

Can you "translate" my prescription to a Leica M diopter? Thanks!

 

Have a look HERE

 

To be more specific one should know with which eye you are looking through the viewfinder.

 

Juergen

[juergen]

Not sure what you mean by that, bolded and underlined. Then why does the Leica diopter I use, a +1, work for ever type of photography, camera position and distance to the subject.

 

You are right. This is correct for the standard Leica correction lens.

I was referring to the possibility of having a lens made to prescription, including cylindrical correction.

 

Sorry for the confusion.

 

Juergen

[ShotCapture]

Have a look HERE

 

To be more specific one should know with which eye you are looking through the viewfinder.

 

Juergen

The right eye.

[scsambrook]

Have a look HERE

 

To be more specific one should know with which eye you are looking through the viewfinder.

 

Juergen

 

Why is that important? Of course, the optician making a prescription lens would need to know ... but I'm puzzled as to any other reason.

[juergen]

Why is that important? Of course, the optician making a prescription lens would need to know ... but I'm puzzled as to any other reason.

 

Maybe it is because I am not familiar with the american terminology

for eyeglass prescriptions, but unless the term “O.S. PL” means that

the left eye needs the same correction as the right eye, it would be

important to know.

 

Juergen

[juergen]

The right eye.

 

 

In your case, with a spherical correction of only -0.5 diopters for your right eye, I would say that

you should easily get along without any spherical correction if we are talking about an M-camera.

 

Nevertheless, the most accurate method would be to follow the advice given by shootist in post #3

 

Juergen

[scsambrook]

In your case, with a spherical correction of only -0.5 diopters for your right eye, I would say that

you should easily get along without any spherical correction if we are talking about an M-camera.

 

Nevertheless, the most accurate method would be to follow the advice given by shootist in post #3

 

Juergen

 

You will be quite correct, as long as ShotCapture doesn't have a problem with astigmatism in his right eye (the cylinder correction). I agree totally that shootist in post #3 has the best advice.

[juergen]

You will be quite correct, as long as ShotCapture doesn't have a problem with astigmatism in his right eye (the cylinder correction).

 

And if he does, like everybody I know, over the counter reading glasses are of no help since they don't correct astigmatism.

 

Juergen

[razerx]

Do you have an SLR with built-in diopters? I used my R8 to get a rough idea what diopter I would need for the M.

[coup de foudre]

the frustrating thing with choosing a dioptre is that your needs may change depending on whether it is a sunny day or low light situation.

 

also, if a magnifier is used, once again the dioptre value needed is different.

[juergen]

 

also, if a magnifier is used, once again the dioptre value needed is different.

 

Are you sure about that? If that were correct, a person with perfect

eyesight would need a correction lens just for use with the magnifier.

 

Juergen

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[coup de foudre]

Are you sure about that? If that were correct, a person with perfect

eyesight would need a correction lens just for use with the magnifier.

let me qualify -- i have found this to be true in my own experience.

 

i have far from perfect vision (some say that's why i'm so fond of blurry images ) and use contact lenses to correct my nearsightedness.

 

for reading, i have no problems whatsoever until my lenses are in and, even then, usually only in low lighting.

 

i typically will use one of my magnifiers (Leica's own) at night with the Nocti or the 75 Lux and most definitely need a dioptre in those situations (i still haven't picked one up though). if i keep the magnifier on the next day to use with my 35, i can still feel i'm struggling. whereas without the mag off, i don't have trouble.

 

perhaps the myth that Leica magnifiers don't dim the image are untrue?

[Shootist]

let me qualify -- i have found this to be true in my own experience.

 

i have far from perfect vision (some say that's why i'm so fond of blurry images ) and use contact lenses to correct my nearsightedness.

 

for reading, i have no problems whatsoever until my lenses are in and, even then, usually only in low lighting.

 

i typically will use one of my magnifiers (Leica's own) at night with the Nocti or the 75 Lux and most definitely need a dioptre in those situations (i still haven't picked one up though). if i keep the magnifier on the next day to use with my 35, i can still feel i'm struggling. whereas without the mag off, i don't have trouble.

 

perhaps the myth that Leica magnifiers don't dim the image are untrue?

 

No it is because the magnifier brings the R/VF image closer to your eye then the fixed distance of 7 feet (2 meters). I use a +1 diopter on the naked VF and a +1.5 when I use a X1.25 magnifier