About the -0.5 diopter of the M11 viewfinder

[kyono]

Advertisement (gone after registration)

Hello everyone, I made a reservation for the Leica M11 at the end of May.

While making a reservation, there was an issue where all the digital red LEDs at the bottom (red LEDs) looked blurred when viewing the viewfinder in the store.

I wore -3.25 diopters of glasses with all my eyes and it looked blurry while wearing them, and when I used the -2.0 and +0.5 Correction lens in the store, the -2.0 looked relatively clear.(With glasses on!)

The question here is, isn't the Correction lens an accessory for astigmatizing users to use without glasses?

I still don't understand exactly why Leica's viewfinder is -0.5.

-0.5 Is it a diopter, so it looks 1.0 for a person with a frameline and focus area (victitious 2m) and has a bare-eye 1.0 vision?

 

 

[Kl@usW.]

Kyoto, wellcome to the forum. Since I'm an eye doctor I might be of help here, although it´s a bit difficult in English: 

For your understanding: -0,5 diopter is the refractive value of all the Leica viewfinders, at least the M´s I have and had. It takes care of a phenomenon that proved to be helpful in the human development : Your eye will shift its focus from infinity to some point in proximity as soon as you have an object moving towards your eye and staying there. Useful for hunting, collecting and so on. But this got "hard wired" into your visual system..... So if you take your Leica and intend to look through the finder, your eye switches to "near vision" . If the refractive value of the finder would be "Zero" you would see a blurred picture--not so with the -0,5 finder, it compensates a part of the "near accommodation".   Unfortunately -0,5  is a compromise: it´s only working for people who don't need glasses or wear correct glasses and are middle aged..... When you are beyond 60 and don't need glasses for infinity, you will have a slightly blurred picture in your finder---and you will need a diopter lens, in this case + 0,5 or +1,0. 

The correction lenses are   for people who don't wish to wear glasses for different reasons while shooting. Unfortunately they won't correct your astigmatism because an astigmatic lens has got an orientation and you would need to turn the correcting diopter 90 degrees for changing the frame  from vertical to horizontal or vice versa. 

Your last sentence I don´t understand. 

summary: 

if you wear glasses wear them while shooting too. If you are under 55 you should have no problem. 

if you are not happy with the frame lines while  wearing glasses, use  the appropriate diopter lens. The value will be different from the values of your glasses and you will need to try a few. You can roughly calculate the value of the correcting diopter, but that depends on your age and knowledge of the  correct values of your glasses.  Contact lenses might be useful to shoot if you are not ( yet ) presbyopic too much.   I advise to go to a shop who has the whole range of diopters and try the values around your prescription. Unfortunately the problem is usually beyond the comprehension of the shop assistants. At least where I live. But  Your optometrist or your eye doctor or an optician should be able to roughly give you the value  of the diopter to start with.

K. 

 

 

Edited June 17, 2022 by Kl@usW.

[kyono]

9 minutes ago, Kl@usW. said:

교토, 포럼에 오신 것을 환영합니다. 저는 안과 의사이기 때문에 영어로 약간 어렵긴 하지만 여기서 도움이 될 수 있습니다. 

이해를 돕기 위해: -0.5 디옵터는 모든 Leica 뷰파인더의 굴절 값입니다. 최소한 제가 가지고 있고 가지고 있는 M은 그렇습니다. 그것은 인간 발달에 도움이 되는 것으로 입증된 현상을 처리합니다. 물체가 눈을 향해 움직이고 거기에 머무르는 즉시 눈의 초점이 무한대에서 가까운 어떤 지점으로 이동합니다. 사냥, 수집 등에 유용합니다. 그러나 이것은 시각 시스템에 "고정 배선"되어 있습니다..... 따라서 Leica를 들고 파인더를 통해 들여다보려고 하면 눈이 "근접 시야"로 전환됩니다. 파인더의 굴절 값이 "0"이면 흐린 사진이 표시됩니다. -0,5 파인더에서는 그렇지 않고 "가까운 조정"의 일부를 보상합니다. 불행히도 -0,5는 절충안입니다. 

교정 렌즈는 촬영 중 여러 가지 이유로 안경을 쓰고 싶지 않은 사람들을 위한 것입니다. 불행히도 난시 렌즈에 방향이 있고 프레임을 수직에서 수평으로 또는 그 반대로 변경하려면 수정 시도를 90도 돌려야 하기 때문에 난시를 교정하지 않습니다. 

마지막 문장이 이해가 되지 않습니다. 

요약: 

안경을 쓴다면 촬영할 때도 안경을 착용하세요. 55세 미만이면 문제가 없습니다. 

안경을 쓴 상태에서 프레임 라인이 마음에 들지 않으면 적절한 시도 렌즈를 사용하십시오. 값은 안경의 값과 다르며 몇 가지를 시도해야 합니다. 교정 디옵터의 값을 대략적으로 계산할 수 있지만 이는 연령과 안경의 올바른 값에 대한 지식에 따라 다릅니다. 콘택트 렌즈는 (아직) 노안이 많지 않은 경우 촬영하는 데 유용할 수 있습니다. 전 범위의 디옵터가 있는 가게에 가서 처방전의 값을 시험해 볼 것을 권합니다. 불행히도 문제는 일반적으로 점원의 이해 범위를 벗어납니다. 적어도 내가 사는 곳에서는. 그러나 검안사, 안과 의사 또는 안경사는 처음부터 디옵터 값을 대략적으로 알려줄 수 있어야 합니다.

케이. 

 

 

So, a "Correction lens" is for the wearer with glasses to see clear frame lines without the glasses?

-0.5 diopters is the value of refraction that focuses on the point 1/x (focal length) ∴x=-2m.

Is it correct that the red LED at the bottom of the rangefinder is always clearly visible when wearing glasses?

[Kl@usW.]

vor 4 Stunden schrieb kyono:

So, a "Correction lens" is for the wearer with glasses to see clear frame lines without the glasses?

Yes

vor 4 Stunden schrieb kyono:

-0.5 diopters is the value of refraction that focuses on the point 1/x (focal length) ∴x=-2m.

No.

+0,5 has the focal length of 2m. A minus lens doesn't  have a real focus, it only has a virtual focus . The minus value of the RF is to compensate for the unintended accommodation of an emmetrope ( one who sees clearly without glasses ) 

vor 4 Stunden schrieb kyono:

Is it correct that the red LED at the bottom of the rangefinder is always clearly visible when wearing glasses?

If your prescription for  the glasses is correct and if you aren't presbyopic beyond a certain amount the LEDs should be sufficiently clear. If you wear multifocal things become a bit difficult because you will have  to look through the correct zones of your multifocals.  Usually that doesn't work. I suggest you go to an optometrist once you have your camera, have your glasses and your eyes checked and, if necessary, get a suggestion for the value of  correcting diopters. 

To be honest: I wouldn't worry too much, you and your M11 will be fine. Congrats btw. 

K. 

 

 

[Choubdia]

Your correction is -2,5 D try it in leica shopping 😉

[Jeff S]

I wear glasses to correct for astigmatism and distance.  At 71, I now find that a plus .5 diopter IN ADDITION to my glasses optimizes viewing and focusing.  As I don’t live very close a Leica dealer, I determined the best result by taking my camera to a local optician and trying their trial diopters over the VF.  Once determined, I ordered the diopter from my dealer. My thin, flexible glass frames allow me to still see the frame lines and focus patch (set to virtual distance of 2m… hence the minus .5 built-in diopter) well. 
 

Best to think less about the math and see what works best for you.  I prefer to keep my glasses on even while using the accessory diopter.  This prevents my having to take glasses on and off and, with sunglasses, to protect against my light sensitivity.

Jeff

[RMF]

Advertisement (gone after registration)

Slightly near sided here with about 20-30 vision and a slight astigmatism. Went to the Leica SF store to try out various diopter strengths and ended up with a -1.0 . Works perfectly as I can focus pretty clearly on the rangefinder patch and clearly see the red LED meter lights. I can pretty much nail focus majority of the time with my 1.4 Lux’s at MFD but the  biggest challenge is that I have three bodies so that means three diopters x$200 USD each 😐. I’ve also lost one off my camera so you need to occasionally check their tightness (I guess I could use blue locktight but that kind of scares me).

 

Edited June 18, 2022 by RMF

[Kl@usW.]

vor 20 Stunden schrieb RMF:

 I’ve also lost one off my camera so you need to occasionally check their tightness

Over the decades I've lost several diopter lenses, the eyepiece of an M 6 and  a x1,4  enlarging eyepiece ..... the get loose while rubbing against your clothes... I now check the tightness regularly. 

[jaapv]

On 6/18/2022 at 2:38 AM, RMF said:

Slightly near sided here with about 20-30 vision and a slight astigmatism. Went to the Leica SF store to try out various diopter strengths and ended up with a -1.0 . Works perfectly as I can focus pretty clearly on the rangefinder patch and clearly see the red LED meter lights. I can pretty much nail focus majority of the time with my 1.4 Lux’s at MFD but the  biggest challenge is that I have three bodies so that means three diopters x$200 USD each 😐. I’ve also lost one off my camera so you need to occasionally check their tightness (I guess I could use blue locktight but that kind of scares me).

 

Yes, the price is extortionate. 

[Besprosvet]

On 6/17/2022 at 2:43 PM, Kl@usW. said:

Kyoto, wellcome to the forum. Since I'm an eye doctor I might be of help here, although it´s a bit difficult in English: 

For your understanding: -0,5 diopter is the refractive value of all the Leica viewfinders, at least the M´s I have and had. It takes care of a phenomenon that proved to be helpful in the human development : Your eye will shift its focus from infinity to some point in proximity as soon as you have an object moving towards your eye and staying there. Useful for hunting, collecting and so on. But this got "hard wired" into your visual system..... So if you take your Leica and intend to look through the finder, your eye switches to "near vision" . If the refractive value of the finder would be "Zero" you would see a blurred picture--not so with the -0,5 finder, it compensates a part of the "near accommodation".   Unfortunately -0,5  is a compromise: it´s only working for people who don't need glasses or wear correct glasses and are middle aged..... When you are beyond 60 and don't need glasses for infinity, you will have a slightly blurred picture in your finder---and you will need a diopter lens, in this case + 0,5 or +1,0. 

The correction lenses are   for people who don't wish to wear glasses for different reasons while shooting. Unfortunately they won't correct your astigmatism because an astigmatic lens has got an orientation and you would need to turn the correcting diopter 90 degrees for changing the frame  from vertical to horizontal or vice versa. 

Your last sentence I don´t understand. 

summary: 

if you wear glasses wear them while shooting too. If you are under 55 you should have no problem. 

if you are not happy with the frame lines while  wearing glasses, use  the appropriate diopter lens. The value will be different from the values of your glasses and you will need to try a few. You can roughly calculate the value of the correcting diopter, but that depends on your age and knowledge of the  correct values of your glasses.  Contact lenses might be useful to shoot if you are not ( yet ) presbyopic too much.   I advise to go to a shop who has the whole range of diopters and try the values around your prescription. Unfortunately the problem is usually beyond the comprehension of the shop assistants. At least where I live. But  Your optometrist or your eye doctor or an optician should be able to roughly give you the value  of the diopter to start with.

K. 

 

 

Hi, I recently bought an M246 and I struggle a bit with focusing, I have both minus something diopters in both eyes (-0.5 on my right eye and -0.25 on the left) and some minor astigmatism (I don't remember how much but it's very little).

With the rangefinder, I focus a bit better with my left eye but it's not the one I like using to shoot. Since all the finders are -0.5 why I still see blurred images with my right eye? Buying an additional -0.5 diopter correction would be useless?

What I struggle with is the astigmatism that can't be corrected by the finder or my -0.5 myopia?

Thank you

[Kl@usW.]

Doesn't  make sense without further information: correct prescription, age, vision corrected 20/20 in both eyes ?   If your astigmatism is really "minor" that won't be the problem. 

[Jeff S]

8 hours ago, Besprosvet said:

Hi, I recently bought an M246 and I struggle a bit with focusing, I have both minus something diopters in both eyes (-0.5 on my right eye and -0.25 on the left) and some minor astigmatism (I don't remember how much but it's very little).

With the rangefinder, I focus a bit better with my left eye but it's not the one I like using to shoot. Since all the finders are -0.5 why I still see blurred images with my right eye? Buying an additional -0.5 diopter correction would be useless?

What I struggle with is the astigmatism that can't be corrected by the finder or my -0.5 myopia?

Thank you

Post #6 still applies.  Correct for any astigmatism first (with glasses), as well as distance, if needed. The focus patch is set at a virtual distance of 2m… this is why -.5 diopter is built in…it’s not meant to be ‘corrected’.   Easy to experiment with diopters after that, if needed.

Jeff

Edited December 19, 2022 by Jeff S

[RMF]

I ended up moving beyond the Leica diopter (I was using -1.0) and went with a custom diopter made by Walter Leica; they are pricey, but works perfectly and fully corrects for my slight astigmatism. 

[Jeff S]

Walter diopter wouldn’t work for me, as I need glasses anyway for astigmatism, distance and sunlight sensitivity… no desire to take glasses on and off.  

Eye matters are subject to individual conditions, preferences and comfort levels.  Best to try and determine for oneself.

Jeff

 

[Besprosvet]

@Jeff S @Kl@usW.

Hi,

today I've been by an optician and tried -1 lens thru the RF with my right eye, it felt perfect, even sharper than using -0.5 (still slightly fuzzy but way better than naked eye), unexpected.

Given that my right eye has been rated (recently) -0,5 do you have any guess why that happened?

Mind that I've looked around the store (so between 1,5 and 3 meters all around me) I didn't go outside to look far and I forgot to frame close objects, do you think I should go back to try all the distances and not only medium ones?

Thanks

[jaapv]

The  viewfinder must be set by the diopter to give the most comfortable eye accommodation between 2 m and infinity with the emphasis on 2 meter. Thus the -0.5 as the built-in value. That will often be a different value from you prescribed glasses   
If you got such a clear result I don’t think that you need  to go back, but by all means do so to make sure. These things are overly expensive. 

[Besprosvet]

1 hour ago, jaapv said:

The  viewfinder must be set by the diopter to give the most comfortable eye accommodation between 2 m and infinity with the emphasis on 2 meter. Thus the -0.5 as the built-in value. That will often be a different value from you prescribed glasses   
If you got such a clear result I don’t think that you need  to go back, but by all means do so to make sure. These things are overly expensive. 

Yeah, can't find a -1 lens for less than 160 euro!

I was just wondering why my right eye would need a stronger lens than I expected, but rangefinders can be little big mysteries.

I may get also a magnifier for 50mm and 90mm focal lenghts, but for that price (Leica 1,4 costs hundreds!) I may give a try to the Bresson for 60 bucks (J version, for short sighted people like me)

[jaapv]

I find those magnifiers not worth the money. Yes, the view is a bit larger, but less bright, less contrast and more narrow. I find them not very effective either. A bit of practice will result in more in-focus shots than such a contraption. If there is something less than perfect with your eye, like a touch of astigmatism, for instance, they will magnify the problem as well. 
still, there are a few people who seem to find them useful. Leica only advises them (are they still being made?) for 135 mm as that focal length is only just within rangefinder accuracy. I think they do so more because of the small framelines. The usefulness, if any has been largely replaced and surpassed by the stick-on EVF. (For digital Ms) Having said that, if I take my time, I can focus 270 mm by the rangefinder. 

[Besprosvet]

2 hours ago, jaapv said:

I find those magnifiers not worth the money. Yes, the view is a bit larger, but less bright, less contrast and more narrow. I find them not very effective either. A bit of practice will result in more in-focus shots than such a contraption. If there is something less than perfect with your eye, like a touch of astigmatism, for instance, they will magnify the problem as well. 
still, there are a few people who seem to find them useful. Leica only advises them (are they still being made?) for 135 mm as that focal length is only just within rangefinder accuracy. I think they do so more because of the small framelines. The usefulness, if any has been largely replaced and surpassed by the stick-on EVF. (For digital Ms) Having said that, if I take my time, I can focus 270 mm by the rangefinder. 

My only doubt is that I have a project for 90mm flash photography... so no EVF possible.

But I'll see how it goes without the magnifier, all in all I bought a 90mm f4 elmar (it's going to be home soon), focus shouldn't be too critical

[Advertisement]

Hallo,

Look here: Interesting Leica gear

[jaapv]

90 mm 2.0 is well within the capabilities of the rangefinder. Absolutely no need for a magnifier.