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Usable eye relief in binoculars (1 Viewer)

Canip

Well-known member
I just finished measuring usable eye relief on virtually all of the binoculars in my collection.

See https://binocular.ch/the-pinac-collection/#collection ,
then click on any binocular in the collection that you are interested in, to find the eye relief / usable eye relief data in the individual posts.

This covers roughly 250+ binoculars and may be useful information for some of you.

Just to sum up again what this is about:

"Eye relief" is usually mentioned in binocular specs by the manufacturer and measured from the surface of the so-called "eyelens" (the outermost lens of the eyepiece), but most often, such information is of limited use since eyecup designs most frequently don't allow you to place your glasses directly against the eyelens.

"Usable eye relief" is measured from the rim of the eyecup (folded down or screwed fully in) and is most often more relevant for eyeglass wearers.

Two caveats regarding the information I provide on my website:

I have tried to measure carefully, but measuring usable eye relief is sometimes not as straightforward as you might think ("uneven" design of eyecups, etc.), so the stated measured values may perhaps be up to 0.5mm beside the correct value. So "12 mm" in fact means anything between 11.5 mm and 12.5 mm.

Plus, e.g. "15 mm" on one bino does not necessarily mean the same thing on another bino, because different shapes, forms and sizes of eyecups will allow you to get closer or less close to the eyepiece with your glasses.

Feedback welcome.
Canip
 
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PeterPS

MEMBER
Thanks, Canip, very useful info especially for people who use their binos with glasses; for people who don't use glasses the diam of the eyecups, the shape of their rubber rims and the way the eyecups fit into their eye sockets are also quite important factors.
 

Chosun Juan

Given to Fly
Australia - Aboriginal
Thanks, Canip, very useful info especially for people who use their binos with glasses; for people who don't use glasses the diam of the eyecups, the shape of their rubber rims and the way the eyecups fit into their eye sockets are also quite important factors.

There are a lot of things to consider, apart from the things you and Canip have mentioned, like most people's faces not being symetrical - this impacts glasses wearers and non glasses wearers alike. The different sizes, shapes and curves of glasses further complicate things.

Then of course there are features of the optical design - such as the degree of spherical aberration, and randpupille which influence the margin of error of the Eye Relief.

Good stuff Canip :t:






Chosun :gh:
 

pbjosh

missing the neotropics
Switzerland
Fantastic resource, chapeau!

I also noticed the APM 6x30 porro that you saw in pre-release guise. A metal bodied compact 6x porro is really appealing indeed! I'll be keen to see a copy when they're available. I'm increasingly dissatisfied with my 6,5x32 Kowa BDII, I just don't get on with it really well - not as relaxed or pleasing a view, in the long run, as I had hoped.

Cheers!
 

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