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Extreme Nearsightedness--Focusing at infinity without eyeglasses (1 Viewer)

Davidae

New member
United States
I am currently shopping to upgrade my binoculars. My #1 hotbutton is the ability of the binoculars to focus at infinity without eyeglasses. I have a -10.5 correction in both eyes, no astigmatism. I would love the ability to purchase APO eyeglass lenses utilizing UD glass at the same quality as my camera lenses. But since our brains are much better at compensating for optical imperfections than digital sensors or film, our cameras and binoculars receive higher quality lenses than our eyeglasses. As a result, I dislike with a passion looking through binoculars with my eyeglasses. An advantage of nearsightedness is the ability to see extremely minute details at short distances. This provides the added benefit of seeing optical imperfections in binoculars, once properly focused, much more than most people. My #2 hotbutton is chromatic aberrations--I can't stand those colored fringes outlining sharp edges, especially in the center of the FOV.

Binoculars compensating for myopic vision at infinity rests in their ability to focus beyond the infinity point (many camera lenses have this ability to allow for thermal expansion). For some reason (I would love to know why), it seems that Porro Prism designs are easier to accommodate this than Roof Prisms. Unfortunately, this function is never listed in the binocular specs, and rarely mentioned on specific models in user forums. For this reason, I will start reviewing specific models and posting the results on this forum. Since my eyesight correction is stronger than about 95% of the population, you can rest assured that if a binocular focuses for me at infinity without my glasses, then they will do just fine for you as well, other eye disorders not withstanding. I would be happy to take requests on specific models for those nearsighted folks that don't have access to a store that carries the model for which they are interested. Just shoot me an email. I will not compare FOVs, nor degree of image stabilization with lesser magnification models (of course there's an inverse relationship between magnification and effectiveness of image stabilization!!!). If you're aware of a binocular model that will focus at infinity without your eyeglasses, please post that, even if you have a rare eye disorder(s). I will only be testing binoculars currently available, however, old models out of production would be of interest.

I'll start off with the binoculars I currently own, the Nikon Action EX 16x50. They are quite amazing, considering they cost under $200.00. They focus at infinity without my eyeglasses very well, although it is almost at the limit of its focusing ability. They provide a very bright image and excellent contrast even at dusk. Chromatic Aberration is minimal, considering the magnification. Focusing is smooth and precise, although I do have to readjust the focus quite a bit. The fit and finish and build quality is quite good, especially for made in China (yes, I still do have an issue with Chinese-made optical products, but there's not much of a choice at this price range). The outer shell is rubberized and fit well in the hands.

I am not very impressed with the Nikon 8x30 Monarch HG. I was barely able to focus without my glasses at an object of about 500 yards away. More than 5x the price of my Nikon Action EX 16x50, with no appreciable improvement in image quality. Very surprised that they are made in China, considering the price. After testing these, I came away very appreciative of my current Nikons.

I am a big fan of Leica and Zeiss optics, and have many Leica R and M lenses, as well as Zeiss lenses. Unfortunately, I was unable to focus at infinity without eyeglasses the Leica 10x42 Trinovid, or the Zeiss 10x56 Conquest. I haven't tested any other models within these two product lines. I have heard, but not confirmed that Leica will make custom modifications to the focus mechanism. I have not heard either way about Zeiss.

I am very impressed with Vortex binoculars. I was able to focus the 10x42 Diamondback and the 18x56 Razor at infinity, without eyeglasses. Build quality, and fit and finish of both models are excellent, comparable to Swarovski. The Diamondback is their least expensive line, and the Razor is their most expensive. It is a safe assumption that every current model in between is of excellent build quality and able to focus at infinity without eyeglasses. The Razor is built in Japan, the Diamondback in China. I was not able to sufficiently test the Diamondback for Chromatic Aberrations, but the Razor was excellent. However, 18x magnification is too high for me to handhold without image stabilization. I was really hoping to test the Diamondback 15x56, but have not yet found a local store that stocks it--for some reason it is a hard model to find, even on the internet. I am also very impressed with the Vortex unlimited lifetime warranty and their customer service. I sent an email to their info address posted on their website, and they responded within 24 hours with the person's first and last name and his phone number. BTW, they are unable to make custom modifications to their focus mechanisms, but it really is a non-issue as it would be unnecessary for me anyway.

The Swarovski 15x56 SLC was excellent as well. Made in Austria. Easily focused at infinity without my eyeglasses and with remaining focus action to spare, and with minimal Chromatic Aberration. To be expected at this price, build quality and fit and finish are excellent. I'm not able to determine if better or worse than the Vortex Razor, as they were tested on different days under different lighting conditions. It is my understanding that for a price, Swarovski will make custom modifications to the focusing mechanism to compensate for certain eye imperfections. However for my purposes, that would be unnecessary.

Finally, for now, are the Canon 18x50 IS image stabilized binoculars, made in Japan. My personal favorite that I have tested so far, and the ones I'll most likely end up purchasing. I found most of the internet criticisms to be unfounded. Sharpness and brightness were excellent, even with image stabilization turned on. They are fully functional without image stabilization, however at this high magnification, the image stabilization is a must when handheld. Minimal Chromatic Aberrations, especially considering the high magnification, and were easily able to focus at infinity without my eyeglasses, with plenty of remaining focus action to spare. Weight is very close to the Swarovski 15x56 and the Vortex Razor 18x56. Without a doubt, I was able to discern far more image detail with the image stabilization than with any other binoculars I have tested, including the Swarovski and the Vortex models. Fit and finish and build quality is a bit more plasticky than I'm used to, however still very good, and will hold up under rainy conditions. The rubber eyepieces I'm told will deteriorate, but at under $20 for a replacement pair, that's not a deal killer for me. A nice touch is the ability to attach screw-on 58mm camera filters and lens hoods. My view is that metal lens hoods would make protective filters unnecessary, however light pollution reduction filters would be an excellent choice for looking at the night sky in urban areas.

Although by no means scientific, I hope nevertheless my comments and reviews are helpful to the nearsighted ones. I would be very interested in what others have to say on the subject of myopia and binoculars, and/or on the models I have tested.
 
Hi,

thanks for the useful data... as for the replacement eyecups - it's probably a good idea to get a pair or two now while they are still easily available. They tend to get rare after a model has been discontinued for a few years...

Joachim
 
The Monarch HG 8X30 works for many users, and it is a much smaller mag than your Action extreme. Do you have difficulty with lower mag glass i.e. 7 - 8X.
 
The Monarch HG 8X30 works for many users, and it is a much smaller mag than your Action extreme. Do you have difficulty with lower mag glass i.e. 7 - 8X.
That's a good question, I don't know. I haven't tested any lower mag models because I don't have a need. I do own an old compact model, Nikon 10x25CF that I bought back in 1987. They also focus at infinity without my glasses. Logically, it would seem to me that the lower the magnification, the more the binoculars would need to focus beyond the infinity point to compensate for nearsightedness. But you raise an interesting question, and I will test a few high-end low magnification models, and post the results.
 
Hi,

thanks for the useful data... as for the replacement eyecups - it's probably a good idea to get a pair or two now while they are still easily available. They tend to get rare after a model has been discontinued for a few years...

Joachim
Don't they make generic replacement eyecups?
 
I am currently shopping to upgrade my binoculars. My #1 hotbutton is the ability of the binoculars to focus at infinity without eyeglasses. I have a -10.5 correction in both eyes, no astigmatism. I would love the ability to purchase APO eyeglass lenses utilizing UD glass at the same quality as my camera lenses. But since our brains are much better at compensating for optical imperfections than digital sensors or film, our cameras and binoculars receive higher quality lenses than our eyeglasses. As a result, I dislike with a passion looking through binoculars with my eyeglasses. An advantage of nearsightedness is the ability to see extremely minute details at short distances. This provides the added benefit of seeing optical imperfections in binoculars, once properly focused, much more than most people. My #2 hotbutton is chromatic aberrations--I can't stand those colored fringes outlining sharp edges, especially in the center of the FOV.

Binoculars compensating for myopic vision at infinity rests in their ability to focus beyond the infinity point (many camera lenses have this ability to allow for thermal expansion). For some reason (I would love to know why), it seems that Porro Prism designs are easier to accommodate this than Roof Prisms. Unfortunately, this function is never listed in the binocular specs, and rarely mentioned on specific models in user forums. For this reason, I will start reviewing specific models and posting the results on this forum. Since my eyesight correction is stronger than about 95% of the population, you can rest assured that if a binocular focuses for me at infinity without my glasses, then they will do just fine for you as well, other eye disorders not withstanding. I would be happy to take requests on specific models for those nearsighted folks that don't have access to a store that carries the model for which they are interested. Just shoot me an email. I will not compare FOVs, nor degree of image stabilization with lesser magnification models (of course there's an inverse relationship between magnification and effectiveness of image stabilization!!!). If you're aware of a binocular model that will focus at infinity without your eyeglasses, please post that, even if you have a rare eye disorder(s). I will only be testing binoculars currently available, however, old models out of production would be of interest.

I'll start off with the binoculars I currently own, the Nikon Action EX 16x50. They are quite amazing, considering they cost under $200.00. They focus at infinity without my eyeglasses very well, although it is almost at the limit of its focusing ability. They provide a very bright image and excellent contrast even at dusk. Chromatic Aberration is minimal, considering the magnification. Focusing is smooth and precise, although I do have to readjust the focus quite a bit. The fit and finish and build quality is quite good, especially for made in China (yes, I still do have an issue with Chinese-made optical products, but there's not much of a choice at this price range). The outer shell is rubberized and fit well in the hands.

I am not very impressed with the Nikon 8x30 Monarch HG. I was barely able to focus without my glasses at an object of about 500 yards away. More than 5x the price of my Nikon Action EX 16x50, with no appreciable improvement in image quality. Very surprised that they are made in China, considering the price. After testing these, I came away very appreciative of my current Nikons.

I am a big fan of Leica and Zeiss optics, and have many Leica R and M lenses, as well as Zeiss lenses. Unfortunately, I was unable to focus at infinity without eyeglasses the Leica 10x42 Trinovid, or the Zeiss 10x56 Conquest. I haven't tested any other models within these two product lines. I have heard, but not confirmed that Leica will make custom modifications to the focus mechanism. I have not heard either way about Zeiss.

I am very impressed with Vortex binoculars. I was able to focus the 10x42 Diamondback and the 18x56 Razor at infinity, without eyeglasses. Build quality, and fit and finish of both models are excellent, comparable to Swarovski. The Diamondback is their least expensive line, and the Razor is their most expensive. It is a safe assumption that every current model in between is of excellent build quality and able to focus at infinity without eyeglasses. The Razor is built in Japan, the Diamondback in China. I was not able to sufficiently test the Diamondback for Chromatic Aberrations, but the Razor was excellent. However, 18x magnification is too high for me to handhold without image stabilization. I was really hoping to test the Diamondback 15x56, but have not yet found a local store that stocks it--for some reason it is a hard model to find, even on the internet. I am also very impressed with the Vortex unlimited lifetime warranty and their customer service. I sent an email to their info address posted on their website, and they responded within 24 hours with the person's first and last name and his phone number. BTW, they are unable to make custom modifications to their focus mechanisms, but it really is a non-issue as it would be unnecessary for me anyway.

The Swarovski 15x56 SLC was excellent as well. Made in Austria. Easily focused at infinity without my eyeglasses and with remaining focus action to spare, and with minimal Chromatic Aberration. To be expected at this price, build quality and fit and finish are excellent. I'm not able to determine if better or worse than the Vortex Razor, as they were tested on different days under different lighting conditions. It is my understanding that for a price, Swarovski will make custom modifications to the focusing mechanism to compensate for certain eye imperfections. However for my purposes, that would be unnecessary.

Finally, for now, are the Canon 18x50 IS image stabilized binoculars, made in Japan. My personal favorite that I have tested so far, and the ones I'll most likely end up purchasing. I found most of the internet criticisms to be unfounded. Sharpness and brightness were excellent, even with image stabilization turned on. They are fully functional without image stabilization, however at this high magnification, the image stabilization is a must when handheld. Minimal Chromatic Aberrations, especially considering the high magnification, and were easily able to focus at infinity without my eyeglasses, with plenty of remaining focus action to spare. Weight is very close to the Swarovski 15x56 and the Vortex Razor 18x56. Without a doubt, I was able to discern far more image detail with the image stabilization than with any other binoculars I have tested, including the Swarovski and the Vortex models. Fit and finish and build quality is a bit more plasticky than I'm used to, however still very good, and will hold up under rainy conditions. The rubber eyepieces I'm told will deteriorate, but at under $20 for a replacement pair, that's not a deal killer for me. A nice touch is the ability to attach screw-on 58mm camera filters and lens hoods. My view is that metal lens hoods would make protective filters unnecessary, however light pollution reduction filters would be an excellent choice for looking at the night sky in urban areas.

Although by no means scientific, I hope nevertheless my comments and reviews are helpful to the nearsighted ones. I would be very interested in what others have to say on the subject of myopia and binoculars, and/or on the models I have tested.
I have myopia in the same range as yours, maybe a little bit less. The Swaro NL 8x42s won't hit infinity for me, but it's very close. I can get one eye using the diopter. A little disappointing, but a quite minor issue for me.
 
Binoculars compensating for myopic vision at infinity rests in their ability to focus beyond the infinity point (many camera lenses have this ability to allow for thermal expansion). For some reason (I would love to know why), it seems that Porro Prism designs are easier to accommodate this than Roof Prisms. Unfortunately, this function is never listed in the binocular specs, and rarely mentioned on specific models in user forums.

Swarovski is to my knowledge the only major manufacturer that lists information about focusing beyond infinity in its specs (they call it „diopter correction at infinity“).

I am currently in the process of updating the information for the binoculars in my collection not only regarding the ability of binoculars to focus beyond the infinity point (I call it „Excess travel of focus wheel beyond infinity position“), but also regarding the range of diopter adjustment - an information lacking often even in manufacturer‘s specs - and the direction of rotation (clockwise - anticlockwise) from close focus to infinity.
See for example the NL Pure 8x42 here:

It will take a few more weeks until I am done, so if you are looking for a particular binocular which is listed on my website „Binoculars Today“ (Binoculars Today – Website about binoculars) but the information has not been added yet, send me a message and I will try to answer your request.

Canip aka Pinac
 
Hi,

First of all, I don't think your ability to discern fine detail at close range has anything to do with your assessment of a binocular's optical deficiencies. Perhaps you have an above average visus.
A binocular is an afocal device and a user with normal vision would adjust the focusser so that rays from a target point source would emerge parallel from the eyepiece, i.e. as if the target were at infinity. In your case the rays would diverge from an apparent source ca. 10 cm forward of the exit pupil.
It's no surprise that you have had more success with high magnification binoculars. In binocular families with differing magnifications the objective focal lengths are usually the same and the higher magnifications are achieved with shorter focal length eyepieces. Consequently the shift of the focal plane of the objective inside the focal plane of the shorter focal length eyepiece has a greater effect on the apparent image distance.
Here is a thread I started over 7 years ago as my alter ego, John Russell: Focus Overtravel (compatibility for the near-sighted). I should point out that the current 10x42 Swarovski EL has a revised focus mechanism and may not achieve the focus overtravel measured on my example.

John
 
I am currently shopping to upgrade my binoculars. My #1 hotbutton is the ability of the binoculars to focus at infinity without eyeglasses. I have a -10.5 correction in both eyes, no astigmatism. I would love the ability to purchase APO eyeglass lenses utilizing UD glass at the same quality as my camera lenses. But since our brains are much better at compensating for optical imperfections than digital sensors or film, our cameras and binoculars receive higher quality lenses than our eyeglasses. .....
Although by no means scientific, I hope nevertheless my comments and reviews are helpful to the nearsighted ones. I would be very interested in what others have to say on the subject of myopia and binoculars, and/or on the models I have tested.

thanks for the useful information about your experience.
It think , will be nice, if other peoples add it's own experience.
small addition from me (glasses -8, 100% vision with ~ -8.5 ... -9):
Zen-Ray 7x36ed2 : can be used at infinity without glasses, remaining some focus above it - I think, limit is ~~ -10 ... -12 dptr.
Zen-Ray 7x43ed3 : can be used at infinity without glasses, remaining small focus above it - I think, limit is ~~ -9 ... -9.5 dptr.
Minolta Activa 7x35 (porro) : can't be used at infinity without glasses, very small limit at infinity. Overally good old style porro.
Minolta Activa 8x42 (roof) : can't be used at infinity without glasses.
Minolta Activa 8x25 (porro) : can't be used at infinity without glasses.
 
I am in the same boat, I have -5.5D in both eyes.

I like Leica but none of their products are adequate, they appear to go to -4D only.

I've had Swaro EL 8.5x42, it went to 6D infinity-wise, just barely enough.

Had Zeiss 8x42 SF, also appeared to go to 6D, just barely enough.

Zeiss 10x54 HT appears to have a more generous -7D correction at infinity with enough room, I like that model most of all.

Always wondered about 12x50 EL and 15x56 SLC. I think 12x50 will be my next buy. 10x50 EL doesn't have enough correction per their brochure.
 
Hi,eye a

First of all, I don't think your ability to discern fine detail at close range has anything to do with your assessment of a binocular's optical deficiencies. Perhaps you have an above average visus.
A binocular is an afocal device and a user with normal vision would adjust the focusser so that rays from a target point source would emerge parallel from the eyepiece, i.e. as if the target were at infinity. In your case the rays would diverge from an apparent source ca. 10 cm forward of the exit pupil.
It's no surprise that you have had more success with high magnification binoculars. In binocular families with differing magnifications the objective focal lengths are usually the same and the higher magnifications are achieved with shorter focal length eyepieces. Consequently the shift of the focal plane of the objective inside the focal plane of the shorter focal length eyepiece has a greater effect on the apparent image distance.
Here is a thread I started over 7 years ago as my alter ego, John Russell: Focus Overtravel (compatibility for the near-sighted). I should point out that the current 10x42 Swarovski EL has a revised focus mechanism and may not achieve the focus overtravel measured on my example.

John
John
if the rays reaching the eye are parallel sided, what is the source of the strange dark shadows we call 'blackouts' or 'kidney beans'?
Would be grateful if you could explain this puzzle.

Lee
 
Repair shops and manufacturers can adjust this, making a bin compatible with us myopics.
If we can find such support.

Edmund
 
John
if the rays reaching the eye are parallel sided, what is the source of the strange dark shadows we call 'blackouts' or 'kidney beans'?
Would be grateful if you could explain this puzzle.

Lee
Lee,

Rays reaching the pupil of the naked eye from a distant object would be parallel and binocular or telescope users with normal vision would adjust the focusser so that the rays from the viewed point source emerging from the eyepiece would also be nearly parallel for a relaxed view.
The angle of incidence of this parallel bundle to the eye would however differ from the angle of incidence to the objective by a factor approximately that of the magnification (angular magnification).

If the binocular were pointed at a wall, then the parallel bundles of light emerging from the eyepiece for different points on the wall would converge and meet at a point a few millimeters in space behind the eye lens of the ocular. This is the exit pupil and is effectively an image of the aperture of the objective lens. It is smaller than the objective aperture by a factor of the magnification.

If the eye is placed behind the exit pupil then we will be unable to see the field stop and the AFoV will be restricted. If however the eye is placed inside the exit pupil, and is just slightly decentred, rays from the field edge will be occluded and we will experience blackouts.
In an instrument corrected for left/right and upright image a downward movement of the eye's pupil will result in occlusion of the lower part of the field.

Another factor that can produce blackouts is spherical aberration of the exit pupil (the Nikon SE was infamous for this), but I think you'll have to ask Henry for an explanation. ;)

Spectacle wearers rarely experience blackouts because eye relief is more usually inadequate than excessive. However three examples I know of are the 30x Wide on my Swarovski ATM, the 7x42 Meopta Meostar and the 8x56 Swarovski SLC, which all require some eyecup extension.

John
 
Last edited:
Lee,

Rays reaching the pupil of the naked eye from a distant object would be parallel and binocular or telescope users with normal vision would adjust the focusser so that the rays from the viewed point source emerging from the eyepiece would also be nearly parallel for a relaxed view.
The angle of incidence of this parallel bundle to the eye would however differ from the angle of incidence to the objective by a factor approximately that of the magnification (angular magnification).

If the binocular were pointed at a wall, then the parallel bundles of light emerging from the eyepiece for different points on the wall would converge and meet at a point a few millimeters in space behind the eye lens of the ocular. This is the exit pupil and is effectively an image of the aperture of the objective lens. It is smaller than the objective aperture by a factor of the magnification.

If the eye is placed behind the exit pupil then we will be unable to see the field stop and the AFoV will be restricted. If however the eye is placed inside the exit pupil, and is just slightly decentred, rays from the field edge will be occluded and we will experience blackouts.
In an instrument corrected for left/right and upright image a downward movement of the eye's pupil will result in occlusion of the lower part of the field.

Another factor that can produce blackouts is spherical aberration of the exit pupil (the Nikon SE was infamous for this), but I think you'll have to ask Henry for an explanation. ;)

Spectacle wearers rarely experience blackouts because eye relief is more usually inadequate than excessive. However three examples I know of are the 30x Wide on my Swarovski ATM, the 7x42 Meopta Meostar and the 8x56 Swarovski SLC, which all require some eyecup extension.

John
Many thanks John.

Lee
 
Bump. Since this is a vital and sorely overlooked point.

Enjoying my Zeiss 10x54 HT, with its generous -7D of overdrive.
 
Just one small niggle.

This is the best graph I can find, and it looks that -10.5 is a bit of an outlier, and somewhat farther out than 95%.IMG_0495.png
 

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