Relation of age and exit pupil (1 Viewer)

Raybo said:

How does it effect us as binocular users?

Is a smaller exit pupil better for us "older" people? As an example, I "can" have blackout problems with my Pentax 8X43 SP's but with my 10X35 E2's it has not occured as of yet. As we get older is there a relation?

Thanks and clear skies,
Raybo

Click to expand...

Swedpat said:

Raybo!

According to what I have read a very young person have an maximum eye pupil of 8mm, after 30 years old it will be smaller than 7mm. After that about:
40 years old: 6mm
50 years old: 5mm
65 years old: 4mm
And finally to the very end of life about 3mm.

That means a person with a maximum eye pupil size of 5mm doesn't have use for binoculars with more than 5mm exit pupil. Using a 7x50 means that half of the light go to waste. If you have 5mm eye pupil and use a 7x50, it means that the 7x50 in practice will work like a 7x35. Then will be better to use a 8x40 or 10x50.

I think blackout problem has to do with too long eye relief, not eye pupil size relation to exit pupil size. I have heard that a big exit pupil size is bad for them who has astigmatism, if I recall right, and a small exit pupil in that situation is an advantage.

Regards, Patric

Click to expand...

Raybo said:

I just hope i'm getting this right.

If my eyecups are extended that does what for me?

Raybo

Click to expand...

John Traynor said:

It changes your eye's position relative to the focal point of the eyepiece. Blackouts can occur when your eye is too close to the eyepiece. Back off a bit and the problem usually goes away.

John

Click to expand...

Raybo said:

Thanks John,

But why do the blackouts occur? Is it because of the exit pupil or is it the way I have the bins orientated to my eyes? The reason i'm asking is because I have less problems with the smaller exit pupil bins.

Thanks again,
Raybo

Click to expand...