Diopter questions...
Old 07-16-2011   #1
Asim
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Diopter questions...

So I'm planning on getting an M6 classic with a 0.72 finder. I intend to use the 35 f/2 and 75mm f/2 lenses.

I wear glasses with a prescription of -2.0. Is it true that the viewfinder is already set at -0.5... which means I should only order a -1.5 diopter?

also, is it easier to see the 35mm frame lines...

1. WITHOUT a diopter WITH glasses on
OR
2. WITH a diopter and WITHOUT glasses on?
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Old 07-16-2011   #2
t.s.k.
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Yes, and # 2

#1 and #2 are relative, however. You shouldn't have any problems seeing the 35mm lines with glasses.
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Old 07-16-2011   #3
skibeerr
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You should test a few diopters in different strengths. Get high quality ones or suffer the loss of crispness in your viewfinder.
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Old 07-16-2011   #4
rogerzilla
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Are such things still available for the M2 and M3? When I get new corneas (long story) I am 90% certain to need glasses for the first time in my life, and the 35mm frame on the M2 is rather close to the edge.
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Old 07-16-2011   #5
ka7197
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Quote:
Originally Posted by Asim View Post
I wear glasses with a prescription of -2.0 dpt. Is it true that the viewfinder is already set at -0.5 dpt ...?
That's right. It means a normal-sighted person will see the framelines and rangerfinder patch at a virtual distance of 2 m.


Quote:
Originally Posted by Asim View Post
... which means I should only order a -1.5 diopter?
Depends ...

Is your -2.0 dpt prescription accurate? Is it recent or from several years ago? Is it meant to make you see properly at infinity distance or at medium distances?

If your -2.0 dpt glasses make you see perfectly at infinity then a -2.0 dpt correction lens will make the rangefinder patch appear at 2 m—which is a convenient viewing distance for most people ... with the possible exception of the elderly. For younger persons, there is no significant difference in accommodation between infinity and 2 m; those who can see sharp at infinity also can see sharp at 2 m easily. However for persons with presbyopia, this is not always the case.

If your -2.0 dpt glasses make you see perfectly at infinity then a -1.5 dpt correction lens will make the rangefinder patch appear at virtual infinity—which may or may not be preferable to you over a virtual distance of 2 m. To find out, I'm afraid you'll have to try both -2.0 dpt and -1.5 dpt correction lenses in person on your camera and see for yourself which suits you better. Or maybe both will suit you equally well ...

If your -2.0 dpt glasses make you see perfectly at medium distance (such as 2 m) then a -2.5 dpt correction lens will make the rangefinder patch appear at a medium distance again; a -2.0 dpt lens will make it appear at virtual infinity; a -1.5 dpt lens at beyond infinity.


Quote:
Originally Posted by Asim View Post
Is it easier to see the 35 mm frame lines ...

1. WITHOUT a diopter WITH glasses on
or
2. WITH a diopter and WITHOUT glasses on?
Glasses will make you lose a significant portion of the viewfinder's field-of-view. A correction lens screwed into the eyepiece won't. So the answer is, "2". Still, most likely you will be able to see the 35 mm framelines in a 0.72× finder even with your glasses on ... albeit not quite as easily as without glasses/with correction lens.


Quote:
Originally Posted by rogerzilla View Post
Are such things still available for the M2 and M3?
Sure. All Leica M cameras share the same eyepiece so you can use the same correction lenses and magnifiers for all of them. However I don't know if the older models also have their viewfinders set to -0.5 dpt (= virtual distance 2 m). They might use a different value, such as -1.0 dpt for example, which would translate to a virtual distance of 1 m.
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Old 07-16-2011   #6
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Fabulous. Thanks.
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Old 07-16-2011   #7
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If it's possible, I strongly recommend trying -1.5 as well as -2.0. As I get older, although my distance optical prescription has not changed (-1.75), I find that the diopter value is more critical. I have recently gone from -2.0 to -1.5 for my M6. For Mamiya, I've gone from -2 to -1 as they don't supply half values. I find that a bit weaker is better than slightly too strong.
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Old 07-16-2011   #8
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My modern Leica diopter screws into my M3 perfectly well.
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Old 07-16-2011   #9
Asim
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thanks for your replies.
from what i understand, maybe i shouldn't be going after a .72 viewfinder at all. perhaps i'd be better served with a .85 viewfinder with a diopter attached. (i'll be using a 75mm and 35mm lens)

so what is a better option for me considering I don't need to wear my glasses with a diopter attached?

1. M6 with .72 viewfinder with diopter attached using 35mm and 75mm lenses.
OR
2. M6 with .85 viewfinder with diopter attached using 35mm and 75mm lenses.
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Old 07-16-2011   #10
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I use a 0.85 M6 with a -1.5 Leica diopter and I can't quite see the four sides of the 35mm frame at the same time. But I don't have to move much to see them. I think I ignore the fact that I can't see them all when taking photos with the 35mm lens, and just use the whole viewfinder as my "framelines". The framelines on rangefinders aren't all that precise in any event.
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Old 07-17-2011   #11
akiralx
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I wouldn't recommend the 0.85 for 35mm.
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Old 07-17-2011   #12
alistair.o
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If it is possible to, I would try a Leica retail outlet and sample some. I have diopters and they are not what the optician suggested based on my prescription.
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