Eye box? (1 Viewer)

[Pinewood]

Hello,

What is meant by the term "eye box"? I did an internet search but I was directed to items about rifle 'scopes. Does the term have any relation to "relaxed view"?

Stay safe,
Arthur Pinewood

 

[Binocollector]

I always interpreted it to mean "relaxed view". So how large the leeway is for having no black outs or kidney beaning.

 

[Pinewood]

I always interpreted it to mean "relaxed view". So how large the leeway is for having no black outs or kidney beaning.

Thank you,
Arthur

 

[Maljunulo]

I think it's another term which sounds as if it means something, but really doesn't.

(yust my opinion)

 

[Pinewood]

I think it's another term which sounds as if it means something, but really doesn't.

(yust my opinion)

Hello Maljunulo,

The term may be used more by users of rifle 'scopes, but it does seem like something that cannot be quantified, like "wow!'

Stay safe,
Arthur

 

[Binocollector]

I think it has to do with the shape of the light cone that forms the exit pupil of the binocular. Things like FoV will influence it. Smaller FoV and larger exit pupil should make for a more comfy "eye box" for instance. But there certainly are other factors involved. I am in no way an optics expert. But comparing a lot of different models -- there definitely are some that are more comfy for the eyes, show less kidney beaning or blackouts.
@Gijs van Ginkel , @Holger Merlitz , @Canip and others might have more valuable input on that question.

 

[tenex]

Other factors in the mix these days include high eye relief and field flattening. The more demands placed on an eyepiece design, the less forgiving it's likely to be in use.

 

[Holger Merlitz]

Other factors are vignetting and aberrations of the exit pupil. 'Eyebox' is a kind of abstract space, composed of the positions and angles which the eye pupil can assume behind the eyepiece while still being able to see something. During the optical design process, the software is placing the eye pupil in a range of positions and directions and judges whether the image would still be acceptable. A wide range would imply tolerance for eye pupil displacements and thus a relaxed ease of view.

Cheers,
Holger

 

[ReinierB]

So I think every pair of binoculairs has an eye box.
One is just a bit more comfortable than the other, due to different factors.

 

[tenex]

During the optical design process, the software is placing the eye pupil in a range of positions and directions and judges whether the image would still be acceptable.

That sounds incredibly complicated. Do the actual results confirm these predictions well?

 

[Holger Merlitz]

That sounds incredibly complicated. Do the actual results confirm these predictions well?

I guess such an analysis is helpful in particular for wide angle binoculars, to avoid e.g. excessive CA near the edges of the field, since in such situations the eye pupil is not neatly aligned with the exit pupil. Modern software is fast and able to check out lots of settings within a reasonable time frame.

Cheers,
Holger