The 10X42 Zeiss SF (black) has the most eye relief I've ever seen with my eyeglasses. It was a true walk-in view AND I need one stop out on the eye cups!
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Eye relief in 10x42 SLC and EL? (1 Viewer)
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oldfortyfive
Well-known member
I don't buy it either. Only my old Vortex Fury 6.5x30 equals it. No others come close.
Look through the binocular.
OK how to test eye relief.
First you need dial calipers with jaws at one end, a dial and scale to read off and a sliding centre piece that you can use as a probe down into the eyecup. Get some thin plastic and using a support across the eyecups to rest the caliper gauge on, use the sliding scale to lower down to the top of the eyepiece lens that you have protected with the plastic. Take the measurement and add the thickness of the protection plastic and deduct the thickness of whatever your calipers were resting on. This gives you the dimension from the top of the lens to the top rim of the eyecup.
Now take a stiff card and calculate the exit pupil of the binos. If you have a 10x42 then 42 divided by 10 gets you 4.2mm. Very very carefully rule two lines on the card EXACTLY 4.2mm apart. Don't press on hard when drawing, make the lines as thin as possible and as accurate as possible.
Stack your binos on top of a support on a table or worktop or bench with the objectives pointing towards a pale coloured wall or if you haven't got that then a pale coloured sheet of card. Using an inspection lamp not a narrow beam torch/flashlight support the lamp so it shines onto the wall/card and reflects into the objectives of the binos. Meanwhile bring the card with the lines drawn on it closer and closer to the eyepieces and have some way of supporting the card perfectly upright and steady. As the card gets closer you will see the exit pupil appear on the card and at first it will be larger than you expect and fuzzy edged. Take the card closer and line up the drawn lines so that as the exit pupil sharpens up and gets smaller it does so inside the lines. When the exit pupil is exactly the size of the distance between the two lines, stop and measure the distance from the rim of the eyecup to the card. To do all this you need everything well supported and square-on to each other and the exit pupil should be perfect round. If it is oval even a tiny bit it means the bino isn't square-on to the card so adjust it until the EP is round. OK now you have the distance from eyecup rim to EP. Add this to the depth of the eyecup that you have already determined and you have the total eye relief.
Is this easy? No. Will you need several attempts? Yes.
Tricky bits? Keeping everything steady and not nudging anything out of position, determining whether the EP just fits inside the parallel lines or is slightly smaller or overlaps the lines a tiny bit.
Persist and you should get within 0.5mm. I don't pretend this method is perfect and I am sure with better equipment it could be improved.
Afterwards a glass of white Burgundy in a dark room is recommended. I think I need one now...............
Lee
First you need dial calipers with jaws at one end, a dial and scale to read off and a sliding centre piece that you can use as a probe down into the eyecup. Get some thin plastic and using a support across the eyecups to rest the caliper gauge on, use the sliding scale to lower down to the top of the eyepiece lens that you have protected with the plastic. Take the measurement and add the thickness of the protection plastic and deduct the thickness of whatever your calipers were resting on. This gives you the dimension from the top of the lens to the top rim of the eyecup.
Now take a stiff card and calculate the exit pupil of the binos. If you have a 10x42 then 42 divided by 10 gets you 4.2mm. Very very carefully rule two lines on the card EXACTLY 4.2mm apart. Don't press on hard when drawing, make the lines as thin as possible and as accurate as possible.
Stack your binos on top of a support on a table or worktop or bench with the objectives pointing towards a pale coloured wall or if you haven't got that then a pale coloured sheet of card. Using an inspection lamp not a narrow beam torch/flashlight support the lamp so it shines onto the wall/card and reflects into the objectives of the binos. Meanwhile bring the card with the lines drawn on it closer and closer to the eyepieces and have some way of supporting the card perfectly upright and steady. As the card gets closer you will see the exit pupil appear on the card and at first it will be larger than you expect and fuzzy edged. Take the card closer and line up the drawn lines so that as the exit pupil sharpens up and gets smaller it does so inside the lines. When the exit pupil is exactly the size of the distance between the two lines, stop and measure the distance from the rim of the eyecup to the card. To do all this you need everything well supported and square-on to each other and the exit pupil should be perfect round. If it is oval even a tiny bit it means the bino isn't square-on to the card so adjust it until the EP is round. OK now you have the distance from eyecup rim to EP. Add this to the depth of the eyecup that you have already determined and you have the total eye relief.
Is this easy? No. Will you need several attempts? Yes.
Tricky bits? Keeping everything steady and not nudging anything out of position, determining whether the EP just fits inside the parallel lines or is slightly smaller or overlaps the lines a tiny bit.
Persist and you should get within 0.5mm. I don't pretend this method is perfect and I am sure with better equipment it could be improved.
Afterwards a glass of white Burgundy in a dark room is recommended. I think I need one now...............
Lee
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Theo98
Eurasian Goldfinch
Or, a good Red Cabernet!! B
Seen these steps before, but lost the bookmarked info...Thanks for the informative details, Lee! :t:
Can't right now...6 more weeks before vision returns...but I'll keep it in mind!!! 3
Ted
Swarovski Man
Well-known member
While the eye relief is only 16mm, I would encourage anyone to try them before dismissing them as unsuitable. I have the 10x42 SLCs and wear glasses, but find them absolutlely fine - in fact, the lesser eye relief means that you hold them closer to your glasses, which gives an increased impression of being immersed in the view combined with a smaller distracting peripheral image of your immediate surroundings.
BTW - I have measured the close focus at 2.90m, which is not great, but better than the advertised distance. Remember also, that this is the equivalent of 2.32m on a pair of 8s.
BTW - I have measured the close focus at 2.90m, which is not great, but better than the advertised distance. Remember also, that this is the equivalent of 2.32m on a pair of 8s.
Sounds like you are short-sighted - with a negative correction you need less eye relief. The manufacturer's figure for close focus is a theoretical value and your accommodation lets you get closer. Try it without glasses and you will get even closer.
John
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Why would that be? I thought relief requirements to see the full field were purely to do with how far your glasses are from your eyes. If there an optical effect of the glasses lenses that varies that?
elkcub
Silicon Valley, California
John is correct. According to Smith & Atchison, "The Eye and Visual Optical Instruments," eyeglasses change the effective location of the eye's entrance pupil. Table 14.1 shows that glasses with positive power (for far-sighted) increase the distance from the eye-lens, and negative power glasses (for near-sighted) decrease the distance. Glasses also change the effective magnification and field-of-view, although brightness remains constant because of a corneal flux density trade-off.
Considerable confusion results from not realizing that one's eyeglass prescription makes a significant difference, particularly at the power extremes. Calculations are complicated, so it's better to just use what works and not expect your solution to be the same as someone else's, even if they also wear eyeglasses.
Ed
Considerable confusion results from not realizing that one's eyeglass prescription makes a significant difference, particularly at the power extremes. Calculations are complicated, so it's better to just use what works and not expect your solution to be the same as someone else's, even if they also wear eyeglasses.
Ed
NDhunter
Experienced observer
Ed:
Your post brings forth the reasons why it is very hard to please everyone,
when it comes to eye relief.
A binocular is first designed for typical users, without glasses, it must be
this way.
Now add in the various issues with prescriptions in eyeglasses.
I don't wear glasses, and find very few binoculars that are not easy to
use, the small pocket types are because of the small diameter eyecups,
and some porro designs with limitations.
The advice to try and see if it fits you is very sound advice.
Jerry
